What rpm stall converter should use?

how much street versus how much strip?

On the Street;
3.91s are usually too much gear for the street (just spinning right thru First) but maybe not with the Caltracs .
3.91s @5500 will get you 44mph in First/73 in Second........ so 60 in Second will be 4500. You said "mild roller" so 4500 will be just climbing up the power-curve..........
There used to be a guy on FABO, name of Yellow Rose who many times extolled 4.56s for street. and the reason I think, is because it gets you about 60= 5400/5500 with those 28" tires. He was a smart man, and I miss him..
The A999 /1.54 Second gear) will get you there with 4.30s, and with a lockup TC will get you 65=3350rpm. Jus saying.

But at the track, in Third gear; 3.91s will get you about 106= 5500; just about right for highest trapspeed with a mild roller cam.

The question then remains;
how much street-driving, versus how much strip?
Your gears are saying strip, so then others have given their opinions, which seem good; ( I know nothing about racing)..