Joe
I received your email and will send you a picture of the gear shift lever adaptation. You are correct in your thinking about the shifter mod to clear the seat. The shifter will radius forward to give you the clearance. I took alot of time and actually bent a piece of rod stock as a template to get the correct angle and radius to keep the shifter away from the seat as well as make it feel comfortable.
Your choice of final gear is lower than I have experienced. A 3.55 sounds like a great ratio for no overdrive. Your setup will yield about 55 mph at 1800 rpm and 60 mph at 2000 rpm. This is a little slow on the rpm and you may have troubles if you live near any hills. The good news is that you can always leave her in 4th gear. Your setup has a 3.76 first gear ratio which will feel pretty good with your 3.55 gear.
As a comparison my 54 rides down the road at 2250 rpm at 60.
What engine do you have in your 37?