Hi Drew, I can help with cutting some of the costs.....

You only need 3oz bottle of Tru Oil.....8oz is overkill and contains enough to do 5 guitars whilst the small bottle usually does me fine for 40+ coats on one guitar or about 20+ on 2 being built and finished at the same time. Once opened, shelf life is an issue as it will eventually start to harden and go off, even when left upside down with just a small pin prick hole in the foil as it states on the instructions.

If doing a nudie natural finish you could also skip any grain filling too. Timber mate over here is about $10 for a small container that would cover well over 20 or maybe even 50 guitars.

Have never used sanding sealer and don't see the point when using Tru Oil as it does that job as you apply more layers and then do the occasional wet sanding too.

For the set neck kits if you ordered tight bond from PBG it only comes in a very small quantity, about 10ml from memory so again, you don't need a large bottle of that stuff either unless you plan many more builds.

And with the sanding, have to agree that on a hollow body it shouldn't need as much effort as a solid body which tend to arrive rough as due to lots of machine marks that need to be sanded off.

Hopes this help to clarify a few ways to cut costs and still produce something decent.