Vac Cup sizing

I have been hanging since Late November 2024 using pretty low weights (1-2lbs). Recently began trying to increase and have some concern with cup sizing and blisters.

I am using a small cup from PMP and fill it up nicely. I use lotion method and ensure all air pockets are removed before beginning. I typically do 9 sets at 5min each. Just pick up weight and get back to the next set.

Is there any concern with staying with this cup size that I am filling up nicely to mitigate blisters as I continue to increase weight.