[tsubaki]

I haven't started on mine yet but got the same setup.
My intentions are to put keel pads in place of the rollers and covering the bunks with Glide Slicks or the like.
This will lower the boat about four to six inches.
The only problem I may encounter is the very front roller as what to do in that location.
But like I said "I ain't started on it yet".
I don't remember if your trailer was single or tandem. If tandem you can also put 13" tires and rims on it to lower the boat and not reduce the carring capacity too much.
When I add tandem to mine I'll make them 13".