lightweight shelter for the Sierra Nevada s

"on thing I would like to know more about are tent stakes and how can you make that work in granite sand that has rocks underneath. "

If you are camping high, at or above treeline, stakes don't work very well… too rocky.
I haven't used (or carried) a stake in the Sierra for the past 30 years. I use rocks.

But being this is BPL, I'm sure others will have different things to say.

Billy

Disclaimer: I have never been to the Sierra Nevada.

I think one type of shelter you should look into are all the different mids out there. Several companies make them in all sorts of shapes and sizes. One of the major draw backs are that they need proper staking to hold up. You can use big rocks as the previous poster mentioned. But there are always the UL "free standing shelters". They have been getting lighter and lighter and you would be able to share the weight with your partner. That's what I would look into if you will always be going with someone else. YMMV

Gossamer gear twinn tarp or grace duo tarp. Both are great. Like the other poster said use rocks above tree line and everywhere else just use titanium stakes.