I think you were right to try the Marmot UL tent, if only because the fly is polyester that will not weigh you down with soaked water absorbing nylon, and be a chore to fold and pack up. And the guylines won’t have to be constantly adjusted to keep the canopy tight in the rain so it will deter wrinkles and sagging, and resist high winds. So it is too bad they sent you a tent with a defect, and perhaps you should consider a replacement. Did you check the amount of overhang on the top ridge of the fly? The fly does come as close to the ground as practicable, not the case with many of the others.
However, another big issue is ability to pitch in the rain without water accumulating in the bathtub floor. As you said, slingfin has a somewhat fiddly solution for that. But their fly is silnylon, with the flaws mentioned above. Ditto for the Big Sky Revolution tents.
Since building packs and tents are a hobby, I’ve spent much time attempting to address the above issues. External poles were not a great idea because they create snow fences on a canopy, that may also possibly be affected by strong winds, which may be one reason why Roger Caffin makes his external pole sleeves narrow.
So those who see only unicorns may be right. But as Mao stated, we may have to take a step backward in order to go forward with an inner tent that repels water long enough to pitch, and is joined to the vestibule beaks that also keep water out; thus doing away with with a huge fly that may get carried away by the wind, and allowing for a much smaller fly. But haven’t seen any solutions of this sort being developed by the sporting goods industry, and you probably don’t want to pin your hopes on that.
So if you are still strong on a self standing tent, you might consider another shot at the Marmot UL tent, and whether the Slingfin approach to pitching in the rain might be adapted to the Marmot, since they are both single cross pole wedge tents. Please let us know what you decide, and how it survives your through hike. One great thing about BPL is that you can dig out and post on an old thread, and the update will appear right along with the current threads. Happy trails!


