Couple of things you can do. My 08 Speedster does the same thing. On every other trailer I've had the bow stop was adjustable...up or down. These aren't You can raise the front of the bunks so the boat is up a couple of inches, move the front of the bunks closer to the center if you can't raise them up, does the same thing.
You can also put the winch strap over the bow stop. When you winch the boat up, the strap will help lift the bow of the boat above the stop. I use a chain with an "S" hook to hold the bow down after it is winched on. I don't tow very far, it is only 3 miles from my garage to launch ramp
Good Luck