You are right, there would be some added coloration for not placing it even closer to the bridge. Placing in the bridge pickup position is a compromise for practicality. The main factors play out a bit like this: This effect only matters when simulating non-bridge pickup positions. The distance to the bridge has an effect mainly on standing waves, not much of the initial pick attack sound. The physics of the instrument and strings makes the effect most pronounced for the string with the lowest pitch, for the high strings the effect is not significant. The worst case scenario is the low E string of a single coil Strat, where this effect would start noticeably attenuating something like the 12th overtone of the low E string. For a HB Strat and other designs which work out better for this design it would start at maybe the 17th-20th overtone, which I doubt will be very audible.
This is one of the major error sources in the design. I honestly don't know how severe it will be in practice, time will have to tell.
Yes, it will be hex.
Thanks for the pointer! I don't know why but I had not considered selling a fully assembled control plate.
Thanks for your feedback, I really appreciate it. I am about to write another post that explains why I currently am looking at having a "breakout" pedal, but I can't really say much in response other than that this is a niche product. I hope to find a bunch of buyers but I don't think it will appeal to as many as for example the Axe Fx.