Probably somewhere in the middle.
260 is way too low, those are just the ones that are *directly* linked, and given our national tracing is piss poor if theyve identified that many there's likely a multiple of that that actually occurred. On the other end, the 250k seems way too high based on what else we know, and from what i've read the methodology on that 250k study was rather questionable.
Honestly, i think if ISU does 15k next weekend (as it is looking) they'll probably be just fine when you combine the 25% capacity with it being outdoors. I'd worry a bit about those in the club section though, that was pretty full when they released that seating chart at 25k fans, and that retains a lot of the indoor disadvantages.