I was hired with 1100tt 250ish ME, and 400 turbine. I think a solid number for regionals would be 2000tt 150me/ or some type of turbine time to supplement light twin time. Also, probably be good to have ANY 135 or 121 experience under your belt if its 135 it should be as PIC.
For The guys who are CFI'ing you can fill in the holes in the 135 outfits once those guy's move up and out. The reasoning is this: its totally different teaching turns around a point or S-turns compared to shooting IFR approaches to mins single pilot at night with no autopilot. Just my .02