I’d stay with 10/30. VW engines have a by-pass pressure valve for oil flow. I’ve red the 20/50 is too heavy when cold, causes a high pressure situation and triggers the by-pass valve when you really don;t want it triggered.

Re: your oil lines….I’d fill the engine with the normal 2.5 quarts. Run it for a minute to get it circulating. Then check the level and add as needed.

As you can see, there’s no “one best answer”  on oil, whether for these old VWs or any other car.  My thoughts:

1. Roy is correct that the oil pressure relief valves are set to bypass at 42-45 psi. Running too thick of a blend can be counterproductive, bypassing the cooler and cause the engine to run hotter. Since you are running a remote filter, you also increase the risks of oil leaks from those hoses and fittings. I blew an engine once by blowing the oil line to a remote filter and cooler in cold weather (Christmas morning, no less – the Grinch stole Christmas!) and for that reason alone will no longer use a remote filter or cooler unless I use the high-dollar braided metal lines and screw on fittings – no more rubber lines and hose clamps for me. I do use and recommend the CB Performance Maxi-pump oil pumps with screw on filters – the only brand that I’ll recommend because it’s a high quality 26mm pump. Cheap pumps have loose tolerances and erratic oil pressure while anything larger than 26mm will produce too high of pressure and bypass also. If you see consistent oil pressures above 40- 45 psi, you’re actually “working against yourself.”

2. I typically recommend people start with a high quality 10w40 synthetic blend (Castrol is also my peferred brand, like Allen). I recommend synthetic only because it clings better to the surfaces after you shut the engine off, and provides better lubrication on engine start, before the oil pressure builds up. Most experts agree that at least 50% (perhaps as much as 75%) of engine wear occurs in the first few seconds after engine start – in that very brief interval before the idiot light goes off. Again, this wear cain  be exacerbated with a remote filter or cooler – because depending on where and how it is mounted some oil can drain out of those lines back into the crankcase. On startup those lines must be pumped full of oil before pressure builds up and starts lubricating the cam, crank and rod bearings. Cam bearings and the cam itself are typically the first internal things to start wearing out in a VW engine, in addition to piston rings. Piston rings are easily replaced during a rebuild/refresh, along with a valve job – but you must split the engine case to replace the cam and cam bearings – a major rebuild. Rod and crank bearings seldom fail due simply to wear… they typically fail only due to low oil levels, contamination, severe overheating or some type of catastrophic failure elsewhere, such as a dropped valve. But, synthetic oil provides better lubrication on startup to all these internal wear points.

3. In a hot climate like where you live, I personally don’t think 10w30 is thick enough for summer driving. It is a good wintertime oil – but these TDrs likely won’t get driven a whole lot in the winter. Summer time protection is the primary concern.  Like Allen, I have successfully run 20w50, but only when I lived in South Texas or South Florida – and as I recall, I used and adjustable oil bypass spring (are they even available any more?) and I have always run a thermostat and vanes to make sure the engine warms up quickly, and maintains an oil operating temp of about 180-230 or so.

My LONG 2 cents, with my rationale.  Your mileage may vary…

John, you are correct that the oil filter only needs about 1/4-1/2 turn after oiling the rubber gasket.  Any tighter than that is only necessary from an “idiot mechanic”.

WRT your problems with the oil drain plate:  I do not use any gasket sealer at all and am bone dry underneath.  Try threading the nuts onto the studs without the plate.  If they seem to “catch” then you might want to insure that all old gasket material has been removed and you don’t have a doubled or tripled thickness preventing your nuts from engaging the stud threads.  It is possible that the studs have become threaded into the sump too far.  You could do the old “two nuts trick” and back them out a bit.  Absolutely do use those tiny crushable copper washers to prevent leakage and when you remove the plate, always use new copper washers and gaskets.  You should not have to use any gasket maker or sealant.    These nuts do not need to be super tight.  There is a torque spec which I forget, but I think it is in inch-pounds.  Not much.  I usually tighten mine with a spin tight screwdriver looking “wrench” to the “just right” spec.

Ok John, I am really going to confuse you now. I live in Tampa, Fl, and the temps here in the summer average about 93 degrees, maybe hotter. (So says the local weather channel). When I restored Herbie 1 year ago, I had my 1968 VW engine rebuilt by “Fisher Buggies”. They only work on VW’s, and specifically build Racing VW engines, and build Dune Bugies Frames with regular VW engines, for the none racer. When they rebuilt my engine, they used Castor GTX 20-50 oil. That is what they recommend I use, and to change the oil every 3000 miles. I usually change it every 2500 miles, and clean the strainer as well. During the engine rebuild,  added an extra deep sump, and a newer style Engine Cooling Dog House, and a newer larger style oil cooler. I also run stright exhaust pipes, with abestos exhaust wrap. I now put in about 3 1/2 qts of oil, upon every oil change. I used a LED Heat Sensor hand held temperature reader, and aimed it on the crank case, just behind the crank belt pulley, and I got a reading of 285 degrees. This was after about a 40 minute drive, in 80 degree (mid Spring) weather. I was quite surprised that the temp was that low. The VW shop here says, engines start to over heat at 320 degrees. I have researched several “Oil Articles” on the VW Samba Web Site, and the over all opinion is not to use Synethic Oil. Many of the guys in warmer climates also said they used Castor GTX 20-50. So this is my 2 cents opinion that I got from VW only mechanics, and long term VW users on Samba.