45w tube orientation

[geartech]

Just a quick question before I button up the new 45w tube and extension install.
How should I orient the water inlet and outlet when I mount the tube?
By the way a 4 inch hole saw from Lowes or Home Depot works fine for cutting the hole in the case.

Plus has anyone mounted better mirror mounts and the pro style head on one of these?
It looks like I have the room needed to put the new ones in I got, the cutter head looks to be the
biggest challenge. At least I have all the optics for my big cutter when I build it if worse comes to worse.