I just use Pam spray for nearly all seasoning, in part because I needed my process to work well for waffle irons, and I did not want different processes for different pieces. I would eventually find that one worked better than the other, and feel like I had to redone those with the lower performing seasoning. After having worked through many hundreds of pieces, I can't think of anything I would not use Pam on. Pam is a blend of canola, coconut, and palm oils, plus lecithin, a phospholipid emulsifier that helps to stabilize mixtures of substances that do not normally blend well together, such as oil and water. I avoid substituting a generic or any other spray, but there are a couple of versions of large spray cans that I generally buy. Pam works well for me, but that may be in part because it integrates well to my overall preparation process. I always finish cleaning with at least 24 hours in lye (even after electro or Evaporust or just plain scrubbing) before seasoning.
I spray Pam directly and liberally on the hot pans, about 350 deg, then let cool and drain. I have not had any problems with the spray shocking the iron, but maybe use a low temperature about 250 if the piece is a holy grail. Note that I do not try to wipe down the hot pans. 1) it is a hassle due to being hot, and 2) there may be an absorption benefit to allow it to cool on the iron. Iron is porous after all. When cool, wipe off all excess with fresh paper towels. Repeat 5x, don't be fooled by "looks good enough" at 3x (unless you are flipping it, and just don't care). The color is robust at 4x, but do one more time. Don't be surprised that the excess oil comes off with loose black from the cleaning process for the first 2 rounds. No amount of scrubbing seems to get it all. Bounty works well as my choice for paper towels, and does not leave much lint on most pieces. I hold the hot iron with thick kitchen potholders that I don't mind if they get dirty. I throw them in the wash every once in a while. I also find that the lye finish then 5 coats seasoning at a minimum will deter any rust for many years, even if just stored. When I do come across a piece that has older seasoning and is showing rust, it is almost always from before I used my current process (10+ years).
I also tried using a custom blend of oils, but really had no evidence of any improvement in performance for the increased inconvenience, so ultimately just went with Pam.
If I really want the seasoning to set, I try to cook with the piece for several months, with routine maintenance of the seasoning. The as-cooked seasoning seems to be the ultimate finish, and you can clean up any blotches with a couple extra coats.
