For a little more uumph out of your .46la you might try a 11x5, the thrust will go up with the increase in rpm's and might lug the nexstar around a little better, but if you can get at least 11280rpm out of your .46la on the 11x6 then i would go to a 12x4, this will be a huge gain in thrust and actually be less load on the engine and will still keep your pitch speed around 45mph which is perfect trainer speed.