Polaroid Originals film and Transparency Dry Lift

I'm trying to create transparencies - I'm not trying to do negative reclamation, emulsion lift, etc.

I've been trying to follow the directions in Adams' "Polaroid: The Complete Guide to Experimental Instant Photography" and a couple of other sources, mainly

1) Trimming the edges

2) Heating the print with a hair dryer

3) Peeling away the backing.

What I'm running into, depending on the heating time I've tried (everything from 30 seconds to five minutes:

1) The image and the white background stay on the front, but any attempt to remove the white will smear off the image

2) It kind of works, but strips on white remain on the back of the image, and there isn't much image left on the clear front panel where there isn't, or chunks of the image remain on the front panel and some on the back

3) The front panel comes off, but the entire image is left on the backing

I've been trying to be methodical about changing variables (temperature, how long to heat, heating the front vs. back, etc), but I haven't made much progress.

Has anyone who's done this before have some suggestions - even if it's just for a decent methodology for working out the right temp/time?,