I would tighten up the other side so they both match up effort and drive it a bit.

see how the brakes feel and then see if the hubs are super hot.

2 hands to turn might be a bit much. Normally I spin them as hard as I can and let go.
It should not move more than 1/2 a turn more due to momentum.

if they stop dead when I let go, I back it off a bit.

but seeing as how you have no more to back off, as I said, I would see how much drag it really is, and it may just be so little it burns off.