Wow man, that is really impressive. I can only imagine how much more unique and special that guitar feels than the Kurt Sig Series Jag.
In all honesty I didn't likely save any money building it myself. It probably cost a bit more than the Fender one, but it is full scale and that feels like a better fit for me. I also had fun just seeing if I could do it. Could I take Jaguar parts and get them to fit ok on a Jazzmaster? Yeah.
It worked out well with the blacktop because I just left off the parts Kurt didn't ever seem to use. No rollers, but the plate is there. No bass cut switch. Just simple toggle, two volumes, and one tone. The Blacktop tremolo movement would have also probably been fine with Kurt because it works really well with TOM's. (Like on the CP Jaguars and Jazzmasters.) No trem lock, but I never really saw any videos with him using a tremolo so basically the tremolo was just used as a stop tail.
In the end, putting something together myself was a lot of fun. Given that making one of these full scale couldn't be done any other way than making it custom (at least the guard and plates) I am pretty psyched on how it turned out.