How much of an overall effect will getting a bigger capacitor on the volume pot do for guitar? Mine is wired as 1 humbucker up to a master volume w/ no tone pots so i could get a hotter signal, would a beefier cap boost the signal even more?
putting a capacitor on the volume pot will do different things depending on how you wire it. there are some ways to wire it so the signal gets a sparkly output when the volume knob is turned down. a way to make the guitar sound extremely dull (same as having a tone knob at 1) at all volumes.

but a capacitor on the volume pot will never boost the signal. "boost" means it amplifies the signal. you need additional power (using a battery in most cases) to do this, by adding an opamp or something inside your guitar.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007

Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.

UG's Best DIY PedalBoard
What he said. It will only cut frequencies. To find out the highest frequency that isn't being cut, use the formula


So a higher capacitor value will reduce treble more.
Schecter Hellraiser Deluxe
Boss DS-1
Crate GTD65

GAS List:
Mesa Boogie Dual Rectifier Roadster
As you have no tone pot what would you need the cap for. Unless your using the treble bypass mod on the vol.