which bulkhead size to use?

[Maverick00]

Hey guys im looking for any suggestions before i go ahead with my plan as follows...

Ive picked up a 45gal tank to replace my current 33gal.
I want to drill two holes in the back pane but i cant decide on the size i should use. Ill be using the same 20 gal sump tank that will sit underneath the display in a custom build stand. The return pump is rated for 1056g/h.
What i was thinking was a 1.5" outlet and a 1" return bulkhead. thanks for any input, this will be the first glass drilling experience as well *crosses fingers*