I wouldn't see it selling out for Hoban-Massillon. Best crowd of the year at Infocision, sure, sellout unlikely. I recall Massillon-Highland there in 2013. Massillon fiiled most of their side of the stands, but not completely and they'll bring more than Hoban. Attendance for the Hoban-Massillon state championship game last year was 16,213. Capacity at Infocision is 30K.
As an aside, OHSAA will probably look for another venue as Infocision is only a mile from Hoban and they play there every year against SVSM. OHSAA regulations state that distance is not a factor, but I think that may be a little close for their liking. Hopefully, KSU is making Dix available.