Simms waders fit

[TroutHunter10]

I'm thinking about buying a new pair of G3's. I'm 5'9 170 with an inseam of 31-32in. According to their sizing chart, a Medium-short is supposed to fit someone with an inseam of 31-32 but I still need to be able to kneel, step over logs/rocks, etc so I'm not sure if theres any room to move.

Does Simms take that into account when they size the waders? Or do i need to take that into account and add a couple inches for better movement.

I have the Redington Sonic Pro's in Med and they fit quite well.