Merlin, my disclaimer is that I've never made a GF pizza base, and certainly not therefore in the TMX. However, I have found that I need to use less water when I make any doughs in the TMX as the blades contribute to so much more mess to clean up! My base recipes are Panasonic breadmaker recipes, which are pretty darn good, but aren't designed to be handled of course. So when I first got my TMX I said 'great, I'll make my usual pizza dough in the TMX instead, and my bread recipe' but it just didn't work out right. They are too wet, and that means a fairly sticky mess to remove from the blades etc in the TMX.
You can't really overwork your pizza dough in the TMX, since any extra working that it gets probably negates the need to rest it. So try adding half the quantity of water, then drizzle the rest in slowly until you like the look of the dough, IF 'too moist' is your problem.