I've never had prints, which have been pressed in a dry mount, return to the curl they had prior to the press. Theory may be one thing, but practice shows that once you press prints and place them in storage they do not significantly curl again.
I do zero squeegeeing. I simply pull the prints from the washer, give them a final rinse them off in running water, and hang a bottom corner with plastic clothespins. After they dry and exhibit typical corner curling, they go in the 210M for 1-2 mins at ~200F where upon removal they'll have a gradual slope from corner to corner. Place in a clamshell and within 1 day they're pragmatically flat.
I don't use any kind of corrugated board, screens, etc. One just needs a press.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.