I found this reference that does support 5 quarts after a fluid change, but it also claims 11 quarts after a complete overhaul.

Chevrolet Blazer 2002 oil, coolant, transmission fluids capacities and cars specifications.

So I guess my assumption on adding 6--7 quarts, or even more, to see fluid on the dip stick seems valid.

So just to put the final nail in for this thread, I did end up about close to 7 quarts of fluid after a change. Learned that this 4L60E transmission takes up to 11 quarts entirely.
Also turns out this "RPM surge" I was describing seem more like a torque converter shudder due to low fluid.

https://itstillruns.com/diagnose-aut...s-5357959.html