Not all plastic levers are created equally. The ones that came with my spin doctor tool set and my topeak ones seem too bulky. The blackburn ones that I bought 15 some odd years ago are thinner and stronger. Night and day difference. Havent tried the Park Tool ones yet. Also.. I dont know if this helps me or not but when I put a new tube in I use baby powder which inevitably works its way to the beads. I use GP 4000s and really have never had any problem. As a last resort, practice, practice practice.