On these VW’s the best “tin” is the OEM stuff. I suggest you use an OEM “doghouse” and cylinder covers (have the cylinder #’s stamped on them). I’d also invest in those little “baffles” that sit on top of each cylinder jug and split the air travelling over the jug fins.
If you are not running heater boxes, be sure to plug the holes in the doghouse that attach the hoses that go to the heater boxes.
Use 20w-50 oil and if you really want to get your hands dirty, install one of those deep sump kits that hold another quart of oil.
If you have just the tin I mentioned, you will not overheat. The other tin that covers the exhaust, pulley area is not absolutely necessary, but doesn’t hurt either.
Keep in mind to check the cooling turbine fan when you change the tin. They develop hairline cracks around the center hub. Not a bad time to replace it with a new one…your’s is probably 40+ years old anyway. they’re not expensive.
Most important again is clogged oil coolers. Be sure yours is not clogged or in need of Lipitor or a stent!
I modified all the VW’s I built for full flow oiling with a remote filter. Big improvement to aid cooling. It requires tapping the block. I did it when I had the engines apart.