Does bulkhead size matter?

[tHeHEYzeus]

I'm new to the world of marine aquariums and I've just recently purchased a tank and have begun setting it up. I went to the pet store and asked them how to set up my bulkheads. Anyways long story short the person at the pet store gave me a 1 inch bulkhead and a 3/4 inch bulkhead. I've got the tank drilled for them so they are permanent. I was wondering which would be better to have as my outgoing flow to my sump and incoming flow from my pump.

I have a 45 gallon show tank and a 20 gallon sump located directly below the show tank as you can see in the pictures I've attached.

Thanks for any advice or help!

Tank.jpg
Sump.jpg