I've had very good luck with the XR200. It's on some customer bikes >20k miles and still going strong. I put about 8k miles on a set of my own... 20f, 28r and 170 lbs... with no problems. They are narrow, which is not in vogue, but it's a fine rim. They are ~25g lighter than the XR19W on average.
With the 11spd dish though, I don't know that dropping to 24r is smart... but 20f should be fine. Go 28r. One way you could save a little weight at more $ is to use Sapim CX-Supers, with CX-Rays on the DS rear. If you are going to use nice hubs don't skimp on spokes. The rims aren't very aero, but take the aero benefit that you can. 3x-radial with 28h.
The Stan's 340 is stiffer so you could go 18f and 24r. It's a shame about the random occasional blow-off. I was hoping to come up with a protocol for preventing that, but I think it just needs a bead hook if you want to be totally secure... or use tubeless tires.
I'd lean towards Alchemy hubs... US made with better service, and better build dimensions.
Thanks so much for responding to my post, means a great deal to me to actually have a wheelbuilder respond.
1) Seems like your more fond of the xr200 than the xr19w. Mostly trying to go with the xr19w to have a slightly stiffer wheel so I could get away with a 20/24 build. Would you say that the xr19w build 20/24 would be durable enough for my application? Or would you still recommend going 20/28? If so I just cant use the gold tune hub I had my heart set on. Fairwheel doesnt carry the gold tune 170 in 28hole.
2) Also, sounds like you think Alchemy is a better bet over tune 170s. Is it just for my application? Care to expand on that? Would you go Elf/Orc Ul? I'm a bit hesitant about the Orc UL, if for no other reason its only been out a month. Also, I'm not sure I can get a industry price on the hubs.
3) Finally, part of the reason I'm trying to stay away from bladed spokes is because, its more of a pain to true them. Its a lot easier for my mechanics to true round spokes. Also, because im not a big guy who will be building a light build, ive heard problems about crosswinds using bladed spokes and really light bikes with light riders. Any thoughts on this?