I threw a MIM neck on squier body.. Does the slight gap on the side of the neck pocket matter? Seems fine but you could fit a pick in there : r/fender
First you need to make sure that the body and the neck of your DiY guitar have been in a dry place for at least 48hrs as the wood volume can slightly change due to temperature.
Amazon.com: 1Set Semi-hollow Guitar kit Fine guitar Body+Guitar Neck 22Fret Fit 335 Style Guitar Project : Musical Instruments
How To (Or How NOT To) Fit and Install a Fender Style Neck - YouTube
Electric guitar neck replacement tutorial
Electric Guitar DIY Kit LP795 Bolt on Neck Mahogany with Quilted Maple Veneer Hardware Gold with Black Fitting - Coban Guitars
Electric guitar neck replacement tutorial
Will a Fender neck fit on a Squier body? — Guitars & Tech
3 Ways to Replace a Guitar Neck - wikiHow
Electric guitar neck replacement tutorial
Fitting Neck in body help | Fender Stratocaster Guitar Forum
Should a guitar's neck be parallel to the body or at an incline/decline? - Music: Practice & Theory Stack Exchange