Ok let me go thorugh a few known things about land yacht rig design.....

The CE (centre of effort) should be or very close to above the CR (centre of resistance) this is normally just infront of the rear wheels. To test this a sailing yacht if you slightly lift your feet from the steering a balanced yacht should continue to sail in a straight direction, if the CE is behind the CR the back end will slide out / or the front wheel will come into the wind, if CE is forward of CR the front end will be pushed away and will go down wind.
There is quite a lot on the forum of how to determine CE / CR.
Now some known stuff on rigs.... a tall high aspect ratio rig has more lift than a low aspect ratio rig..... but a yacht with a tall rig tips over easier than a low aspect rig.
Upright masts give better lift but the sail then becomes quite touchy to get positioned correctly with sheeting angles and rig twist, a raked mast has lower lift but is much more tollerant to sheeting angles.

Often designs evolve depending on the sailing location ie. A windy beach location with soft sand and beginner sailors, a low aspect ratio rig with a raked mast would be best, A hard surface like salt / ashfalt and moderate winds and with experianced sailors an upright high aspect ratio rig would suit best.

I know it hasn't answered you question directly but it will give you some thing to think about....

www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/How-to-find-the-balance-points-for-a-Landyacht/