I could lower the whole trailer with:
1) Smaller wheels/tires (could get 1.5 inches)
2) Raising the axle an inch (could get 1.0 inches)
3) Correcting the poor design of the Cribs (Could get 3.25 inches)
Seeing that I could gain a lot by changing the cribs, that is my first plan of attack, I will be testing the boat this weekend. If I can launch at Shirley's then I am done. If I still can't launch then I will try the more extreme axle/wheel modifications.
Here are some photos for those that are interested or may want to try the same mod. Took about 4 hours.
The boat sits about 3.5 inches above the roller. I figured I would take 3.25 inches off the cribs (since I didn't want to risk making the boat sit sloppy on the trailer).

I notched out the crib holder brackets first. I mirrored the notch at the other end so it effectively sits right on the trailer frame now and can't move forward or backwards. This allowed the bolts to be significantly downsized (since they are no longer holding the weight of the boat).

I then used a spacer board to make sure I got the right depth on the bracket that is welded to the frame. I used a saws-all to cut the brackets. I needed to leave enough "meat" to pass a bolt through later.

Finally I re-mounted the crib itself and bolted the two brackets back together. You can see the nice tight fit as the brackets nest together.

End result - Boat sits REALLY NICE on the trailer now (and it's easier to climb in and out of! A benefit I wasn't expecting).

I then re-adjusted the boat guides and am looking forward to a test launch!