Hey Matt this decision is made purely by how your kart is handling. If you feel your kart is to tight coming out of the corners you probably will want to run the 6.0’s . But if you feel like you don’t have enough grip run the 7.10’s. When you run the y-pipe the majority of the people run 7.10’s though.
Personally I would get used to the kart first then decide if the kart and your driving style works better with the 7.10s or the 6.os