I have OSB 5/8's right now and was screwed in with 1" screws and finishing nails and everything else.
I have maybe 3 per joist nails-screws




On top of that the Idiots cut the 2x4 Sole for the wall,Then go and hide it with a vanity for the next 20yrs untill we decide to do the bath.
So I'm taking the floor out and putting 3/4 in with Glue etc to make it right

These are the screws I use going to use that I bought

All plywood always gets installed with the face grain perpendicular to the joists. So the long direction across the joists. I'd be using longer screws and make sure they're not drywall screws.
Pictures are nice. What are your plans for this room? Have you consulted a span chart to verify the joists are up to par if ya doing tiles?
Jaz