Are you using a High Flow PV?
Have you tried increasing the IFR's (beyond .035") all around? You may not be able to cruise on the transition circuit very long with your setup.
I would not go leaner on the HSAB's in your situation. You are correct, this would just delay the mains.
What is smallest HSAB that you have tried?
My "guess" would be to go smaller on the HSAB's and larger on the IFR's to richen up the transition circuit to main circuit lean spot.

How much testing have you done with the front jets? It is hard to pin point when the mains start (even while watching and charting off of an A/F meter), but have you tried going up on your main jets with the smaller HSAB's to see if this helps down low in the rpm range?


Would you mind reminding me which QF carb you have?

Thanks allot for your replies.