That is a good question...Hope someone can answer it.
I'm thinking with the that inch and modifying the bulge a bit I would have enough clearance.
You said the 20's are taller then the balloons were too? That wont work for the tracks so I would have to go with 19's maybe?
Would this thing float with 19" tires on it?
I'm gonna get a pic up of just where the tracks were rubbing.
I didnt mean to highjack your thread here, sry man.
If I could just get a number for the local Attex dealer I could get this all figured out!