Interesting video. Thank you. He seems like a very nice chap. Clearly demonstrates the value of the metric system. If you do need to divide a random length by two, it’s easier to step it out with dividers. The actual figures don’t matter. Making a paper template will avoid pencil marks and rubbing out.
Switch on the press a bit earlier.
Don’t slide the tacked print between the boards in the press. Sooner or later, you’ll catch the print and ruin it. It will inevitably be the one that was most difficult to print or the one where you’ve lost the neg. Make the sandwich on the bench and then slide it in.
Happily, all the setting-out for a mat is done on the back.