Just saying that you might get some additional input if you mention what models you are considering.
On the forum I sold a Little Giant 4-MD-SC 1/10 HP, 850 GPH
and currently use the Little Giant 4-MDQX-SC 1325 GPH, 1/10 HP in my set up.
Both had plenty of whirlpool power for my 15 gal keggles and Duda plate chiller.
In consideration of building a larger rig I bought this:
Its a BEAST!!
I still have it if you are interested. I changed my plans about a bigger rig.