Yes, I think that changing to the 470k's does dirty it up a little earlier in volume sweep. I think a couple other things you could consider are splitting the cathodes on V1 to give you a bit more versatility from four inputs and maybe playing with the V1a plate resistor value. I also lessened the slope resistor value which I like. Just my 2 cents, you may not like any or all.
The degree of any change will be affected by the relative channel volume settings, but I don’t even at the most it will be that much.
Overdrive will still happen at the same power output and SPL levels.