Now that's a nice paint job.
I'm curious about the method you have used, which is new to me. What exactly is "sign mask product" ? Is it a type of paint ? This paint lifted with the stencil removal. What did you change the second time around - Results are amazing !
Sign mask is product used to make stencils (this is the light blue masking I have machine cut, visible in the pics before painting) and available from sign making supply companies. It is in low tack, however getting ready to paint the 2nd colour (blue) I have placed it over the first colour (Red) possibly before the paint had time to harden and when dry peeled paint off with it. Cheesed 
! with the result, I started again this time using adhesive vinyl. The final artwork you can see is coloured vinyl, not paint. The cabinet vinyl was not put on in one run, instead a piece at a time (less cost), however the backbox artwork was grouped (red then blue).
The vinyl can be applied simply by taking accurate measurements of original artwork & transferring them onto the cabinet &/or back box. The vinyl used is 5-7 year rated for exterior use, so should last for quite some time.
Really interesting method, but obviously it worked out well and looks fantastic !
