I generally find nickel-wrapped strings to be a bit warmer. Stainless sometimes just seems to have too much honk for me.
Not really up on the choices available in short scale. I really have resisted flatwounds as they're just too flat sounding for me. Although they'd certainly do that old school Jamerson/flip top sound easily. If it were me and you want to steer clear of roundwounds, you might consider some of the various 'ground' or 'half-round' style strings, where round wounds have been run through a flattening process of one sort or another.
J o e y
