Another batch of my TMI custom made neck plates just arrived just in time for my latest build.
Contrary to some talk on the net, fitting a heavy neck plate does not automatically give a bolt on neck guitar better tone (no such thing) or more sustain. To believe this outright is to have no clear understanding of either the intricacies of guitar design and construction or basic physics.
In very (very) few cases it does in fact appear to increase sustain, slightly, however several other factors are MUCH more important. The fit between neck and neck pocket, the length and type of screw and the stability of the neck plate itself all have more affect than weight alone.
In most of my tests over the years, a LIGHTER neck plate (with these other factors addressed) gives me better results more often. When I make a guitar I try all 3 to see if 1 sounds any better, and if there's no audible difference, I go with what looks best.
A standard Fender neck plate weighs 45 grams with some aftermarket "heavy" versions weighing over 200 grams. I make 3 different weights for my guitars from a thick aluminium plate weighing 20 grams to 2 different stainless steel versions weighing 40 and 55 grams.
Like I say, in most cases it makes no audible difference but I personally prefer the lighter plate when it does. Like most aftermarket "mojo" parts, changing your string gauge or brand will make more difference in tone and sustain than the expensive part you just forked out for.