Minnetrista, MN
I replaced the full cab decals of an Iron Maiden LE about a month ago due to bubbling. It was relatively easy though very nerve-wracking to a beginner as I've never done it.
Decal Removal:
* Use heat gun and plastic scraper/plastic razor blade - heat the decal at one corner and use the plastic blade/scraper to start it peeling up. At this point you can use your fingers to grab the decal and simply keep applying pressure to peel it off as you use the heat gun to soften the adhesive as you continue to peel until you have gotten it all off
Decal Adhesive Removal:
* the BEST by far adhesive remover is RapidTac Rapid Remover: https://www.amazon.com/gp/product/B01MSFD50H/ref=ppx_yo_dt_b_search_asin_title
* spray it on - wait 60 seconds then use a plastic razor blade or scraper to remove the adhesive - may take a couple passes of this to get it down to bare cabinet
Cabinet Prep:
* ensure cabinet is completely smooth with NO bumps or imperfections as they will show through, get all old decal residue off!!!!
* Once old adhesive is off, I used another RapidTac product - Rapid Prep - to clean the cabinet prior to decal application: https://www.amazon.com/gp/product/B006RMQCFW/ref=ppx_yo_dt_b_search_asin_title
Decal Application:
* i used the 'dry method'
* begin by test placing the decal on the cabinet, get it aligned and then use some clamps to secure it down to the cabinet
* once the decal is aligned and clamped down, lift one end of the decal and peel back about 4-5 inches of the backing and lay it down by gently stretching the decal flat
* use a plastic squeegee with felt end to smooth the end flat: https://www.amazon.com/gp/product/B01DY6SXHS/ref=ppx_yo_dt_b_search_asin_title
* remove the clamps now and grab the backing - continue to pull the backing to keep the decal taught as you go. Use the plastic squeegee to continue to flatten the decal to the cabinet as you slowly remove the backing doing small increments at a time
* here is a good video of the process:
* NOTE: the front decal is much more of a pain in the ass as the decal gets so thing around the shooter rod housing. I haven't found a good place to start, but managed to get it laid down ok 
