Was this in AmpliTube 4 or 5?
I’ve found the power amp update in AT5 has made a lot of the older models more useable. I’m actually getting good results from the ‘65 Twin from Fender 1 in AT5.
I particularly like doing my own “Fender factory upgrade” by pairing the ‘65 Twin with the 2x12 Open T J120, which is a vintage Twin cab loaded with JBL D120Fs from AT Jimi Hendrix. This was a factory upgrade that Fender offered. It gives the ‘65 Twin a bit more bite.
You do still need to crank the amp volume to 10 and feed it a hot input.