Thanks, and I am glad this stuff helps someone else. I don't know about "awesome build" just yet. Ask me again when I'm done
I did buy a few specialist tools. I will attempt to rank them in usefulness based on my experience so far.
Most useful: 12' radius sanding block, fret crowning file. These two made leveling and crowning the frets a breeze.
Slightly useful, but could have survived without it: notched straight edge. It made getting the neck straight very simple, but it's also fairly expensive for a tool I might only use a few times. Other people manage to get the neck straight without one. Better value for money the more guitars you plan on building.
Slightly useful, but could have survived without it: fret rocker. Again, it was helpful for identifying high frets (relative to neighbours), but the process of marking frets with sharpie and sanding with the radius block takes care of high frets anyway.
Haven't used yet, but likely to be in the "most useful" category: Nut files. I haven't installed the new nut yet but it's hard to imagine getting it right without these files. Maybe wet&dry glued to feeler gauges?
Didn't buy: fretboard protectors. I just used low-tack masking tape and worked slowly and carefully on the frets.