Your lucky to be able to fish the Sacramento Delto area. I grew up in Vacaville, CA area and went out lots of times with the pops and his buddies for striper, mostly launching out of Rio Vista. They didn't do any fly fishing though. This is what I remember from those days. Most fish came off of some kind of baitfish like anchovies and sculpins, so I would assume the best technique is some kind of streamer pattern. I would stay entertained fishing the banks with a hook and worm to catch the sculpins in the rocks, then the guys would use them on their rods.
I do remember throwing rapalas in the backwater slough areas for young juvenile stripers, with an occasional big one, but I hear there is some great largemouth bass fishing with smallies coming into play as well, only if I was fly fishing back then and old enough to drive
You can catch juvenile stripers any time during the year, with the fall migration during the winter months. We also used to fish some of the marina/dock areas, especially when the DNR would come and stock rainbows at the launches. Now that is a feeding frenzy!
I wish we had stripers in Minnesota, they have to be one of the most hardest hitting fish in North America and strong as well. Don't know much about the Resevoir land locked stripers, but the ocean fish were in insane.
I would definately seek out a good fly shop in the area or I would hire a fly fishing guide for a day or two, it would be well worth the money, especially if you live in the area.