IMO, 5 each would be just fine. 10 judges total. We already get 9 at big events, and 7 at small ones (which can be bumped up to 8).
We already can see that this judge did a good job with the GOE, but dialed in on the PCS. So if we just had 5 focusing on GOE and 5 on PCS, it could work, giving them more time for each category.
I agree that if we had 9+9 judges for an event, a small fed would be damaged. Just that IMO we don't need to go that far.