We use an MSR Hubba Hubba HP. 2 vestibules not to heavy between 2.
What do other challengers use when sharing a 2 person tent?
Balancing weight with room, ease of pitching and sturdiness

I use a 2 person tent for just MEEEEEEE ☺️

For us a Nallo 2, I have also used it solo. Plenty of space, good w/p ground sheet, erects outer first (good for Scottish conditions) the down side is it uses bendy poles. Ours have not broken but I always think it a bad sign when tent manufacturers include a temporary pole repair sleeve when you buy the tent, this does not inspire confidence.

Been looking and trying tents for years and my best for me so far for one person is the Shangrila 3 with single inner. However trying to find a good weight and sturdy two person tent at good price is hard.

Most lightweight 2 person tents are around 1.5kg and expensive but based on reviews not the best in severe winds.

As such I am resorting to my Decathalon Ultralight quickhiker2 for this event which I have used many times with the wife on trips. It is 1.95 kg but very robust, is above average on space for two people, very storm worthy as it has been factory tested to 40-50mph winds and can say I have been out in wild weather in it and been fine. Best bit is it is only £110.

My choice: North Face Tadpole, the old one. I have been using it for about twenty years, a great little tent. A bit cozy but big enough for two, and abolutely a joy to put up. No pegs needed, very stabile in high winds, would hate to replace it.

Andre Hilhorst

Only had it a couple of months, but the Terra Nova Southern Cross 2 is performing very well so far...

For us the "Terra Nova Solar 2" has been brilliant for 7 Challenges and many other trips. (Note;- NOT the Solar 2 plus!)
Replaced the Flysheet a few years ago due to UV damage (3 months in French sun). New pole due to my clumsiness and new zip on inner. Forgotten how much it weighs - as long as I can carry it I don't care.
Hoping it will last 3 more TGO's - hate spending money.