I would suggest making it little bit harder to hit aliens/humans than it is on R Funserver even with lowping.
And another lagged/unlagged thing is that lowping players are on lagged very advantaged, I dont know if is it unavoidable, but it could be more balanced.
That was meant generaly, In lot of games not even the quake 3 engine are lowping players stronger, because more of their shots hit the target, and its similar like they had a bigger hitbox.