Trucks & Trailers - Trailer Set Up, Wheel Clearance question

I bought a 2005 Pathfinder 2000V on a Magic Tilt, single axle trailer. The trailer has four flat
2x6's that the boat rests on, similar to a bass boat. The trailer had a new torsion axle installed prior to my purchasing it.

I am concerned about the clearance of the boat between the fenders, which are not original. The boat seems to sit too low, which allows it to rub on the tires when I hit a bump. It could be that the trailer is too narrow for the boat. I would like to correct all of these issues, but want to do it right the first time. I can't seem to find what I am looking for in regards to trailer set up. I am attaching photos of the side with more clearance; the other side has roughly half this much clearance, but I can't show an accurate photo, as I had to remove the fender to get home.

I have seen other trailers with twin 4x6's that the boat set on. What is the reasoning for using each one? Is this a legitimate way to raise the height of the boat?

I'm assuming you loosened the fender and pulled it away?

I'd get a set of 4x6x10s and turn them on the side...carpet them and put them on in lieu of the flat bunks on the outside (you will need 8 L brackets, and the corresponding hardware.)

Using 4x6s will get the boat up a bit higher and give you some additional clearance.

I'm assuming you loosened the fender and pulled it away?

Not in the photo. They are bolted to each step-bracket.