have never built a guitar but I wouldn't try myself.
in a guitar factory the neck fitting is done by a trained/specialist worker who fe uses shims in the joint pocket to get the neck on correctly.
(had this on my Squier fe ), not sure if the neck and neck pocket on a kit are prepd to go on a 100% straight...
I have done refrets, fretwork and setups but really if you want to save money -> go to a tech/luthier.
after bying good tools, you'll need to do a lot of guitars to break even.
if like me, you like the 'adventure' and like to learn it.....sure go ahead.
oh, for less money of the kit, you can get a simular guitar from Vintage (in lots of colors/editions/types), just with the Wilkinson economy (china) and maybe better Wilkinson (Korea) pu's......not the best Wilkinson's you get with the kit.
google: vintage v6 strat