Tested transfer of a full letter size sheet to a 12"x12" sheet of 3mm acrylic. Heat from iron warped it instantly. Not so much due to the size or soft surface from the last test. Attempting to transfer pattern to plastic for cutting.
Started using Hammermill color laser gloss paper instead of the of the prior gloss inkjet paper. Much better transfers and release than the prior stuff I was fighting with. After 2 minutes of soaking the paper had floated away from the acrylic on its own.
Messed around with some cold toner transfer using mixture of acetone and denatured alcohol. Didn't keep good track of the ratio. Works great to acrylic so far. One transfer had some crazing, but this might have been due to stress from excessive clamping force and not the solvent.