2 - 1" Overflows Enough?

[Jaws]

So I'm going to be returning approximately 1000GPH to my main display from my sump. I have two 10 linear external overflow boxes that are drilled for 1.5" bulkheads. The rest of the plumbing is 1" and I'd like to use 1" pvc for the overflows as well for a couple different reasons. Will two 1" overflows be enough? Any worries of clogging with only 1" overflows? Thanks in advance.