Legally you can run anything. It’s over 20’. Allison does not recommend anything heavier then a 200XS. But there are boats out there with big blocks And happy owners. Robert Cross and I will tell you that the 200XS is fast enough and fuel efficient. Someone else, maybe JR will tell you that a 300XS is fine.
I had a 200xs on my XB03 for about 15 years. Now, I have 300xs with about 220 hrs. The 300xs is the clear choice to me once setup correctly. I removed the the hydraulic jackplate for a manual and went to lithium trolling motor batteries.