Old thread, but I figured I'd add my two cents for whatever that's worth. I don't know what everyone else thinks of it, but I've been just using
PNP Blue toner transfer film. I got a bunch of it for a project a few years ago, and now I have enough that I've never bothered trying other things since.
I've used magazines, foil, PET film, and release liner from self-adhesive vinyl stock. The magazines worked okay, but I never had luck with the rest. The PNP Blue adds an extra bit of coating to the overall thickness of the transferred deposit. I get a lot less pitting of copper pours than with the magazines or any kind of toner-only transfer.
As far as cleaning, my old board stock tends to be dirty and tarnished. I use scouring powder on it until it has a uniform matte finish and passes a water break test after a thorough rinsing. I wear nitrile gloves throughout the process to keep from making fingerprints on the fresh board.
For the transfer, I used to have an old fuser assembly out of a laser printer, but it was really difficult to make it work uniformly. The success of the transfer is a function of heat, pressure, and time. Uneven movement in the fuser or the laminator I tried tends to result in transverse bands where it gets squished too much and isolation dimensions are reduced.
I since made a flat, temperature controlled platen for the hydraulic press. I just throw the board on a phone book or something compliant and insulative. I've found that a moderate temperature (105°C) and a high pressure for a moderate time (maybe 10s) tend to work best. Using a lower pressure means you'll need higher temperatures and/or longer press time. Excess time and temperature means the toner will tend to flow more, and you get a lot more distortion and isolation reduction.
Considering the amount of pressure I'm using, it's easy to see how using a clothes iron becomes impractical for anything but really small boards. To put this in perspective, if I put the platen in the drill press (as an arbor press), I'm limited to about 330-360 lbf (measured with a load cell). This is almost always insufficient total force to get reliable results.