I am looking at getting back into karting after a LONG time off. I anticipate running X30 Masters (390# on MG Reds), and X30 Senior (365# on MG Yellows) - if I want to try hanging with the fast young kids! I have pretty much settled on an OTK, mainly because of good support, and well regarded tuneability.
I am looking at a mix of racing on grippy tires (MG Yellow) and harder tires (MG Red). From what I can see, the 32mm is definitely the ticket for MG Yellow, whereas the 30mm would be better for masters racing, club racing etc (MG Reds). But since when I race reds, it will likely be in Masters, at a higher weight…I am leaning towards 32mm.