Let me summarize my own method, but skipping over a few things like the necessity of pre-drying materials.
I first of all mount a sheet of drymount tissue to the back of the print, within a temporary sandwich of museum board on both sides.
To keep the heated tissue from sticking to the board, I use a slip sheet of release paper between them. Since this sheet can be used over and over again, a single roll of release tissue I bought 30 years ago still has plenty left on it. But individual release sheets or l0-count packages of them can be bought, like from Talas, a bookbinding supplier. In other words, more like a $30 expenditure at most, rather than $300. And you can get all kinds of sizes.
When that has cooled a few minutes under the big glass weight, I pull off the release sheet and set it aside. Then I trim the print plus attached mounting tissue to precise final size at the cutter station.
Then this is taken back to the mounting station. Once the trimmed print is positioned precisely in the manner I want it on its
final museum board mount, I use a medium heat teflon tacking iron to immobilize a place in the center of it, then that goes back between a sandwich of two the larger pieces of reusable museum board for sake of the final pressing. Then back under the glass weight to cool (Drymount tissues like Colormount and Drytac Trimount achieve their final bonding upon cooling).
This procedure works far more efficiently and precisely than the old traditional method fooling around with the tacking iron
beneath the print.
NEVER put a sheet of release paper between the print emulsion/face and a hot platen. You risk transferring an unremovable slick spot to the emulsion.