(1) The poles Tarptent sells are standard Easton aluminum poles, but of course they are not as strong as trekking poles. I doubt that any tent poles are! I got the optional poles for a 3-person Rainshadow 2, and it definitely requires two tent poles while it can be used with one trekking pole. (However, it is far more stable with 2 trekking poles than with one!) You might check with Ruta Locura which makes carbon fiber poles which are supposedly stronger than the usual tent pole, although undoubtedly still not as strong as trekking poles. Personally, I won't take a step on any trail without trekking poles, but of course Your Mileage May Vary. An expensive but lightweight and strong solution might to buy the Gossamer Gear telescoping trekking poles (LT4) and remove hand grips and little baskets to make an extremely sturdy tent pole.

(4) The reason you see many more testimonials about the Double Rainbow is simply that it first appeared about 7-8 years ago, while the Stratospire was new last year. It has absolutely nothing to do with the relative merits of either tent, just with the time each model has been around.

You might be able to work out an arrangement with Henry Shires to send you both tents at the same time, and you decide which to keep and which to send back. It just takes a bit of timing around your credit card billing cutoff dates.

That being said, while I own several Tarptents, I don't have either of these specific models. I therefore can't answer the rest of your questions.

I do know that that it's just as important to tie down a free-standing tent as one that is not free-standing. The former have been known to take off quite frequently in windy conditions when not properly staked down! I personally don't pay any attention as to whether or not a tent is free-standing.