I've had a 1.5" x 1.5" pre press for a while. Mine cost me $15 at the local metal shop. I saw the rosin evolution has a press the same size and sells 2" x 3" bags for it, so I ordered some 160 micron bags. The bags I have been using are 37 micron, great for hash, but not flower. I have been pressing flower raw dawg. I also ordered some pre-cut 1.5" x 1.5" parchment pieces, and got a free timer by using promo code 'pedro', thanks to Pedro's Grow Room, check him out on IG, Twitch, and YouTube.
I pre-pressed five grams of Creme Brulee flower and put it in a trimmed down bag. That was pressed at 95°C for four minutes. I don't have a pressure gauge, but slowly added pressure for the whole four minutes.
Final yield was exactly one gram for a decent 20% yield of some fire!