Running a YS 91AC with 14x10 @ 9700 rpm has no difference from running a 91FX with 14x8 @ 9700 rpm?
I used the same formulas as Thrust HP for Thrust, and it only considers diameter and RPM:
Thrust = 2.83E-12 x RPM^2 x D^4
MotoCalc seems to do a good job at approximating thrust values...180 oz of thrust and 194, respectively for the two props mentioned at 9700. I'll have to explore how it is done there and once I come to an answer, update the spreadsheet.
That said, your change in pitch did have a big change in pitch speed, from 73 mph with the 14X8 to 91 mph with the 14X10; a 25% increase.