Funny! I also camp at altitude in the Rockies...at or above treeline...and rain and high winds are a daily problem...
My primary shelter for 4 yrs. has been the "long" Campmor/Equinox poncho-tarp (58 x 104, 9.5 oz., $69.)
Erected in a half-pyramid, with three walls to the ground and the support pole set at 3.5 feet, this shelter has been a rock. I can sit up inside it, I have 8.5 lineal ft. along the back wall to sleep in, and, it has kept me dry through the most violent wind-driven rain-storms you flatlanders could ever imagine.
After sitting out one gale-force storm above Conundrum HS, I noticed that the rushing water had dug 8" deep gullies under my Mylar groundsheet, but my gear and I remained dry.)
Later, while walking up to the Hot Springs, I noticed campers in expensive ultralite tents who were outside literally wringing out their sleeping bags...
Just 9.5 oz. for my shelter AND rain gear that totally covers my pack.