High five to your better half!!!!
Unfortunately Nitro, this choice is a subjective one for you. You probably wont know which one is best for you until you feel it. The good news though, as Kimbas points out, is that as you are building it, you can shape it to your liking.
Or get DB to do some modifications.
Here's a couple of points I'd make. and I am noooo expert. nor am I an expert guitar player, probably on the upper side of beginner.
1. The Basswood body is heaps lighter than a mahogany body. So your SG and PRS will be lighter than any of the LP models;
2. the LP body, although heavier, is actually smaller (but thicker) than your
ST-1;
3. The LP and SG models have a shorter scale length than the
ST-1. there are a number of effects on playing style, but most noticeably in standard tuning the strings on an
ST-1 feel tighter than an LP. Some say its easier to bend the strings on a shorter scale length. Personally I don't find string bending on a
ST-1 harder, I just have to bend the string further to hit the same note than on an LP.
4. I find that the profile on the LP and SG Models are more of a "C" shape whereas the profile on the
ST-1 is more of a "D" shape. However, if there is any difference in the width, to me its not noticeable. I do not have large hands either, so playing "Hendrix" style chords are always a challenge on any of those models. In practice I don't find one neck smaller or easier than the other, they are just different. the face on the fretboard of all models is comfortable to play chords, bend notes etc without falling off.
5. Sometimes a narrow neck is not easier anyway. I used to have a Yamaha Pacifica years gone by. and the neck was the smallest I've ever played. I could get my hand around it much easier than any other guitar. However, with a smaller neck I found that although it could get my hand around the neck, my fingers on the fretboard were cramped...so it wasn't a preferred size for me.
6. If it were me, I would build a kit that was completely different to the
ST-1. Hell, you know you've got GAS like the rest of us. You're eventually going to build them all anyway! I see you've already gone for humbuckers, great start, try a set neck, some bindings, different wiring or some mahogany for a tone wood, or a kit with a cap. Now that's scary! (just jokes....no but really it is..nah just kidding ya)
Hope that helps, not confuses.
Good luck Nitro. I know you'll love any kit that you get.