4h or 5h most likely. Unless the only option was 588 hybrid. In that case I'd have to do some heavy thinking.
Hawk are you having that much trouble with the 588 hybrids? Last thing I saw was your printout from your session with the 588 5h and it looked great. Are the Srixon fairway woods more shallow faced than the Cleveland 588's?
Are the 588 Altitude irons in 4 or 5 be a solution?