Lower radiator hose - who is using what?

I just measured the diameters on the water pump necks:

Actual measurements, using digital calipers:
top neck lip: 1.85"
top neck behind lip: 1.75"
bottom neck lip: 1.76"
bottom neck behind lip: 1.65" (42mm? or 1 5/8"?)

Not real sure what the right move is for what size lower hose to run. Those with running cars - what lower radiator hose are ya'll using?

I ordered a 1 3/4 to 1 1/2 adapter last week. It's not here yet. I'll report back when it gets in.