pot value for signal coming out of tube preamp?

[Guitarjunkie]

I have a tone king royalist tube preamp on the way. If u aren't familiar, it's the same kind of preamp pedal as the friedman IR-X and all those others. I plan to run it into the return of my SS combo. But i need a volume boost for any time i need a bit more volume. (not drive, just a sightly louder signal) Generally i accomplish this in several ways depending on the rig,and in this case i intend to build a box with 2 jacks and a pot from the output of the preamp to my amp return. The way i use it is i turn the pot down just enough so the volume is slightly less and thats my normal volume setting. Hitting the switch bypasses the pot and thats my "boosted" volume. The question is, how can i determine what pot value to use so that it's not too big a value so its super touchy to adjust the volume where i want it, and not too small a value that i can't drop the volume enough. I just need to drop it maybe 2-3 db i would estimate. Like turning a amp master up maybe 1/2 a number. Far as i know theres no line/guitar level switch on it, but i guess most returns on a amp like my modeler are probably optomised for guitar level like the input is, so the royalist is probably guitar level meaning a 250k would probably be fine? Thoughts?.

[phatt]

A 50k pot would likely be ok, it depends on the input Z of the return circuit in the amp you are using.
Phil.