I am building a Infinity 90 with the MVVS 91 (rear exhaust config)
Have ordered a Perry VP-30 just in case. Those long fuel lines (12-13 inch) give me head ace.

For the MVVS I think 14x8 APC will be a OK choice for a start. Maybe try some bigger props later.
For a 120.. 15x8 and bigger seems more correct.

Sorry for my crappy E