Get some smaller angle brackets(the ones that bolt onto the cross-members)
and that should lower the boat 4" or so. It looks like you can lower the
front supports by just re-clamping them lower.
It might be possible to move the bunks out so the boat rides lower?
If you lower the bunks, you should consider getting a center protector on
the cross-members to protect the bow when you ride up the trailer while
loading, and be carefull about the axle also. If you hit a big bump you
don't want the axle to jump up and damage the hull.