Very cool T'Mater,
One word of caution, as you have been vegging these guys out under florescent lighting. You are going to want to harden them off prior to putting them into full sun. I would put up some type of shade cloth, and gradually remove it over a week.
Make sure your plastic green house doesn't get too hot. Remember it's designed to retain heat. Are you in an area that is/was seeing those double digit temp. numbers?
Oh, and what is this rain you speak of? Is that the stuff that falls out of the sky in the winter?
In the winter I let it fill my reservoir, then adjust my p.h. and
nutrient PPM after...remember rain is generally pure good water. Though I think you might get a hell-of-a-lot more rain than I do. You might need to devise a cover...not plastic!!! Remember our little green house heat retention system...same thing, and you don't want to cook your roots.
I've seen some of the farms that run Crop King equipment cut Styrofoam "plugs" that the plants grow up through. Might be worth looking into if you get that must rain.
Todd