Just got my Predator in the mail this week, and while it’s not been in the water yet I discovered a seal-trimming tip you might find useful. The product manual recommends a spare pair of hands to hold seals tight while trimming. Great in theory but not so great if you’re in a hurry and no one’s around to help.
My solution was to use one of those plastic cereal bag clips; the bigger the better. They help keep it stretched out in a straight line and also give you a straight edge to cut against. Even better, it helps stop you trimming too much off in one go. Hope this proves useful.