check the wiring again, even if its pot of other value(be it bigger or smaller) in there, it shud not have the effect of turning the pot and not much changes in volume level
between 500 and 250k or even bigger value pot for volume control, it will make you geetar sound much brighter(higher the pot value goes, the brighter/more glassy it is). The smaller the value, it will darken(muddified, warm, or whatever anyone wanna call it for the dumb mojo tone) the sound. Usually info says 250k for single coil and 500k for humbucker, but any other value is fine as well.
To have a bigger impact/change on the sound, in term of brightness or darken it, the pot for volume control has a bigger role than using different value for the tone pot.
The bigger the value, the brighter the sound can be, but also increasing the hiss/noise level. It aint a perfect world
Using 500k for hss config(if having only one main overall vol control) prolly be a good combination, considering the humbucker in bridge postion. 500k for single coil also pretty much ok(personal preference for me to use 500k for single coil)
heh, anyway, since also cant see things in forum, imho, do check thru the wiring again