@
Robvolz
This seems like a simple equation but is not, the 2.5, 5mm or what ever can be a pretty big deal.
The extra or less arm length is multiplied around the arm travel of the stroke making it have a far bigger impact than it would seem.
2.5mm crank arm increase = 15.7mm stroke travel increase X rpm = potentially a lot.
Whether or not you can optimize it depends on fit, fitness, maladies, gearing, etc.
The 177.5's on the Strawberry make a huge difference going up Mt. Tabor which is a miracle for me as I have little to nothing for hills with a 38in. inseam.