Deere says your 755 gets 12 x 5 (AM102094) or 12 x 7 (AM102095) and a 6 x 12 R1 tire or a 7 x 12 tire for 4WD. they say you want a 23 x 8.50 - 12 in R4 if you are considering them.
in the rear, you need an AM102099 16 x 6 used with a 7.2-16 or 8.3-16 R1 tire. An AM102098 (16 x 8) or AM119728 (16.5 x 9.75) on 12 x 16.5 R4 tires.
The 4WD issues are to keep the tires from scrubbing during extended use on hard pavement. You guys might also want to debe the R1 & R4 directionality, since loader work usually benefits from having traction in the direction you need it most. (I dig out the swamp a lot and therefore I need the traction in reverse, not forwards). Therefore I have the 'preferred' direction reversed. I got this from the owners manual, so its not just my wild and scary imagination.