Bilge pump 1" or 1.5" pipe preference

[IHC]

I have a manual muster simms bilge pump on the boat and plan to relocate it. Relocation will result on about 2mtrs of pipe from bilge to pump and about 70cm head. Two 90 degree elbows will also be involved. Question is will it be best plumbed on 1" or 1.5" pipe. I'm thinking the 1.5" will move more water, however the 1" would clear any air in pipe more rapidly upon initial use.

Your thoughts are welcomed...
Thanks Ian