FWIW, I’ve built this recently and did a lot of research on the original pedal that I believe inspired the Killer Bee. I actually think the A50k tone and the B50k volume is more consistent with that original pedal. It’s the way my kit was supplied and it works just fine IMO.
Also, the kit came with a 5k trimmer which also worked fine biasing the J113 to 6 volts with little difficulty. I’m guessing a 10k trimmer would work just the same; maybe just a little more sensitive than the 5k.
Not trying to make a big thing here. Just trying to emphasize the point made here that either values for pots and trimmers would likely work equally well.