I’ve had good luck with Black Magic masks too. I’ve built two 1/48 scale B-24’s and one B-25. The masks are a life saver. I’ve found the masks can be a bit too tacky. The instructions recommend pressing the mask to the palm of your hand before applying to the model to reduce the tackiness. I’ve also found some of the more complex, compound curve masks tend to stretch and not stay down. I have used these as a master and cut the mask out of Tamiya tape.
Use a toothpick to remove any paint seepage. Use “Goo Gone” to remove any glue residue the masks might leave.
Be sure to let the Future dry for at least 48 hours.
Good luck.
Jim