shower drain flange

I just installed the shower drain in the shower I'm rebuilding. It'll be a tiled floor (pre-slope, pan liner, mortar & tile). The lower flange of the shower drain lifts off the plywood ever so slightly (maybe a 1/32" of an inch) instead of sitting perfectly flat. As I can't screw the lower flange in place without messing it up, I was wondering if I could apply some glue to the bottom of the flange & weight it down till the glue sets. Is this a good idea? Am I worrying over nothing? If I do this, will the PVC cement bond to wood, or should I use some other adhesive that's safe for PVC.

I'd really appreciate some insight from those who travelled this path before me.

Thanks so much,
Richard

picture please

richard

post picture please. What brand of drain?

david