Hi James; thanks for reaching out.  Hopefully these comment will help.  Cool that you are building the baritone, it will surely be great. yes, I find the hollow body approach worthwhile although I am still experimenting with it. My effort is to have an adequate acoustic sound and still keep a relatively slim profile, so I continue to mess with different designs as I would suggest that you also do.  I even retrofitted a broken acoustic guitar with lap steel 4 string board on top and it sounded great.  just doing that gave me some more ideas.  As far as the A headstock I just visually laid it out with the angle hopefully keeping the string alignment reasonably straight.  I suspect there are templates on line by other builders, but so far I like the simplicity of what I am doing now although on a couple 4 stringers I have used a slanted 4 in a row configuration which I also like.  I did make a 4 string baritone lap steel from a water ski and tuned it to C. that works fairly well.  On those I also configure a resonator box to attach to the bottom of the ski, board, and so far have not used volume or tone.  using output jack only again to keep things simple.  Many of the players I build for are perfectly happy with that.  Less to go wrong electronically.  Hope this helps.   Nice to be able to communicate with other builders.  Write again with any other questions or thoughts.

Ron

Here’s that info about the tuner measurements, the headstock template is in there, scroll down a bit? https://www.buildyourguitar.com/resources/lapsteel/index.htm

Piezo info: https://www.cigarboxguitar.com/knowledge-base/using-piezos-in-cigar-box-guitars-part-1-piezo-basics/

Saw this & I thought of you? https://m.youtube.com/watch?v=PHI2jaLzWfY

I've enjoyed helping you with some of your builds. You've got some good ideas. I think you'll end up being a top notch builder. I sent a friend request too.

I feel you about the neck, that’s why I recommend Glenn’s video, he shows how super easy it can be if shown properly? Good luck on your builds ;)