Someone on the Speedster forum just bought one of these wood Derringtons and it’s a screamin’ deal, imho. Like half price. I might get one myself–even though I already have the coolest steering wheel you can put on these cars…
Get this Derrington, (OR THIS ONE!) and this adaptor boss, and it should bolt right to your existing kit. I think you’ll have to source or make a horn button but so what?