My indoor basement stair treads are currently made of 5/8 OSB nailed to the stringers.
I plan to replace them with new glue+screw plywood.
I'm considering 3/4 Baltic Birch ply for this because of its exceptional stability and exterior-grade glue on all layers.
I'm also considering 1-1/4 plywood but I wonder if the thicker+fewer layers and different adhesives actually make it less performative.
Cost differences are negligible.
Is Baltic Birch appropriate for this use? Should I prefer 1-1/4 plywood?
I'm aware of the code for height of risers and it's not relevant to this decision.