release paper is fine but you need to keep it clean. I use parchment paper (under a sheet of mat board) in sheets which is dirt cheap and can be tossed if it gets dirty or wrinkled. I also do not own a tacking iron. I just never got around to buying one but the regular iron I use works pretty well, just a little large for the task. I use shot bags for weight on top of something flat, Having a piece (or two) of 3/4"mdf to put on top of the mounted print is handy too since it will remain pretty flat over time. It's also the heaviest thing around. 3/4" gator board works well too if you have enough weights.