How do you know when you have the thermostatically control choke set right for leanest burn?

I have a Rochester BC carb on my 54 Chevy sedan. I rotated the coil spring setting on the front of the carb a few notches for lean burn. Car seemed to burn nice and lean on the flat runs(clean exhaust - no black soot at idle anymore), but when the lady and I went for a road trip into Virginia, we lost all kinds of power climbing the hills north of Sparta, NC. A number of times I had to drop down into first gear and we're talking foothills folks, not the Cascade Mountain Range.

Anyway, can anyone share some lean burn setting hints for the 235 L6 Blue Flame?

Cheers from NASCAR country


Spito, spitero, huchtooey splateus!
1958 GMC Series 100 stepside
1954 Chevrolet Bel Air 4-DR sedan
1966 Chrysler Newport 2-DR hardtop