Have a '69 Ghia coupe. Am in the middle of the conversion so can only offer a few insights. Car has 44 CALB 100AH cells, an AC-51C motor, and Curtis 1239 controller. To me the motor is just the right size, I only do surface streets. The car is so much fun to drive.
Have had two issues. Both were simple and due to being a newbie. First one was due to 50 year old wiring. Was solved by cleaning up contacts and getting rid of wires from past aftermarket radios and gauges. Second was due to not programing the controller for my application. Got a handheld programmer and not only solved my problem but is a heck of a lot of fun changing the settings such as regen.
What I wish I understood when I was starting out:
The car is now torn apart and am redoing things. I read this and did not take it to heart. Sort of like having kids. No mater what people told me it would be like I did not understand it until it happened.
First: Rewire the car. The wiring harness kits are not too expensive and it is getting rid of many ghost issues
Second: Install the motor
Third: Install the battery. Make a model of the battery box out of cardboard or foam. Then make the box
Forth: Install everything else around the motor and battery
The other stuff such as wiring, gauges, and the charger are fun and make it look like it is coming together, but the battery placement is key.
As to your question on Autostick. A fellow I know with a Corvair conversion likes it. Tried it on the Ghia and did not like it. Have an IRS and I like it. Much simpler.
Look at the images on the web for where to place things. Videos and images from EV West have been a great help with finguring the layout and buying stuff that I break or want to change. Fast delivery. Parts for my conversion came from EV4U. This suited me as I want a hobby car and will be constantly fiddling with it. They have been quite helpful in answering my questions. I like to understand what I am doing and why which is what they are really good at.