WD
$240 to save 7 ounces is not too cost effective at over $500 per ounce to save weight - better to save weight in the new tent. I think you use the tarp because you like the space, so I'm not sure how you would feel about the solo - double tent thing as far as space. When I started carrying a $500 pack I decided to buy a big enough tent to keep my pack inside it with all of my gear.

I know its non-obtainium but my favorite UL tent for the last 20 years has been a SD Flash Magic - a single walled version of the flash-light that weighs 3 pounds 4 ounces with the stakes and everything. Its barely large enough to hold me and the pack but it works. (backpack tent)

I have an original Bibler Eldorado and I can attest to its ability to stand up to ANYTHING mother nature can throw at it. The roof vents are awesome but it weighs 4 pounds 5 ounces and I do not know what the available versions might weigh. I am taking it snow camping in the Three Sisters Tuesday night for an expected snow storm. (mountaineering tent)

I would feel better above tree line with the potential for strong winds and storm to be in a dome tent with three poles crossing over me. This is the most wind proof silent tent design. The Biblers with 2 crossed poles are lighter and ceertainly strong enough, but they do flap a bit in the wind if it comes from the wrong direction.

I'm not sure I would want a tent with any mesh in the body - thinking of the spindrift problem.

I saw a nice montebell solo tent on ebay - 2.5 pounds.
Jim