I put in two sets tonight (see the BK:SOR thread for those pics). Was the first time I have done it.
I did BK first, and honestly made it harder on myself than I needed to. I removed the playfield (which is crazy easy with the Spike). First one I did the wet method, spraying the sticky side down with Windex. Wish I wouldn't have. It honestly slid around too much...maybe I used too much or something. It took forever to get it positioned just right and then squish enough Windex out for it to stick without it sliding more. Pain in the butt. For the other side, I just peeled back and cut off a few inches of backing. I used the bolt hole to line it up, and made sure it stayed straight along the top edge. Just sticking it down lightly in one area allowed me to pull it off and reposition pretty easily. Once it was lined up well, I stuck that back end down better, then peeled off the rest and worked my way to the front carefully. They are nice and thick, so I had no issues with bubbles or creases. Went on easy.
Did BM66 next. This time I didn't bother taking out the playfield. For the first side, I pulled the pf forward on the rails, and lined up the back end few inches similar to what I did on BK. I left the the rest hang and super carefully flipped up the playfield. From there I could peel off the rest of the backing and work my way forward again. The second side I just left the pf up. I peeled off about half the backing, from the back end to just past where the playfield stood. Then just simply slid it carefully between the pf and the wall, lined it up in the back (slightly tight squeeze behind the pf, but not bad) like usual, and was extra careful to keep everything straight. Once that was down good, I peeled off the front half and again slowly worked my way forward. I was a little worried about the area I couldn't get to because of the pf, but again the blades are thick enough that it didn't wrinkle or get crooked over that couple inches. Next time I do it, I will most likely do it again this way.
The first one I did, with the pf removal and Windex easily took longer than the other three did. Having the pf out definitely made it easier to just eyeball it, but wasn't worth the extra time or hassle. Not to mention how careful I had to be getting it back in, not wanting to wreck the pf or the blades. If I had someone home to help, it would have been much easier lifting in and out. But if you are careful, taking it out really isn't necessary.