Cover cropping and green manure

I live on a half acre in an arid high desert region with poor desert soil. I have several large raised beds on the property already, as well as fenced off animal enclosures, but am looking to improve the rest of the existing soil with some kind of a mixture of cover crops to build up my existing soil without tilling it. My goal is to cover every inch of it with growing things by fall. We intend to get more fruit and nut trees. I could chop and drop it or use it as a ground cover...it matters not to me. I'm just not sure which would be a better way of building the soil up the fastest?

I have rye, oat groats, crimson clover, and daikon radish and kodiak mustard in good quantities. Does anyone else have any suggestions of things I could add? Or a recipe for a good tried and true mix for my arid climate?

I am looking to plant this mixture over a newly built hugel berm around a bunch of spaghetti squash vines to hold in moisture and crowd out any weeds and to hold the dirt layer over the top of the wood and manure. I would greatly appreciate any input from those who have been this route before!

hau, Becky,

Your list is a good start indeed, I would add some pea and buckwheat seeds to those you have already and broadcast the mixture. I would probably do half my seed first run and then once it has sprouted go back with the second half of the seed mix. This give better opportunity for full coverage and water retention.
I would let the cover grow till fall and then chop and drop. Then replant with winter cover items.

Good idea on broadcasting half first and then filling in after sprouts come up. Thanks!