A config program is a good idea but care needs to be taken that more time is not spent updating the config program than you spend enhancing the core code. That said, what I read in here is than many people would like to upgrade older telescopes goto but are either unable to deal with soldering or they, like me, are more than a bit scared of even the configxxx.h file. At first, I had absolutely no idea what the variables did. I read, I asked, and, as you know, I made mistaiks (oops). However, my stumbling around eventually bred some understanding and now it works although I still don;t understand exactly why.
I printed the configxxx.h file and read it like a newspaper over and over until I got my head around the logic. It was hard to understand, even from the comments, how to configure my device. Perhaps more comprehensive commenting (instead of a user manual) would help more. "This variable changes xxx so that yyy may go faster, slower, whatever." A real dummies, simple guide.
Maybe that would help. The problem is, YOU know exactly what each one does. I and maybe others do not. I have found the best way for me to be sure that I understand something is to explain it to someone else. I discover this when explaining things to my son when he was about 7. I could explain things simply and concisely only if I fully understood it myself.
The lack soldering skill is a problem as is sourcing probably unfamiliar components. I wonder if EasyEDA could supply fully populated PCBs perhaps without the Teensy. I know Seeed Studio do this but in runs of (I think) 10+ boards. This minimum quantity might put you and/or Howard into selling finished boards. Selling working boards would certainly increase your numbers but, warranty and support would probably be a nightmare for you.
The above is just me thinking and writing at the same time. Two things at once is never a good idea for me...