I just replaced my original build surface with a buildtak like surface from my friend Mark at Peopoly. Basically, I peeled off the old build surface and cleaned the magnet with alcohol to remove the extra adhesive. Then to avoid bubbles under the surface, I submerged the magnet in a pan with water and a drop of dish liquid (homemade application fluid).
Peel the backer off of the new surface, slide it under the water to avoid bubbles, and squeegee them together. After they're attached, take it out of the water and give it another squeeze.
And after it's dried for a day or two, cut to size.
I've only run one print on it so far, but no issues to report. I did notice that the new material was about twice as thick as the original, so maybe that will help with the bubbling and lifting issues that I had on the first one. I'll let you know how it goes after a few more prints.