To change Roadsmith tires, you just jack up the rear end under the jack points using a scissors jack. The jack point is the bottom of the shock mount. Once the trike is up about 5-6 inches, there is plenty of room to pull the rim/tire off. The problem this guy is having is that the fenders have no radius and you can't jack the trike high enough to slip the rim off the studs.
If I owned this trike, I would radius-cut the fenders for clearance. Once cut, the cut would only need a trim edge to mask the cut and the trike would look better (IMHO).
For GWJessie... how many miles did it take you to wear out the rear tires?