Mountain Biking - Spokes and nipples questions

I weigh 250 lbs. and am planning to purchase wheels with XT hubs and Mavic F519 rims for use with rim brakes. My bike is full suspension and my riding habits are XC and easy to moderate trails. I'm confused over what spokes and nipples to request for the wheel build. I read some who say that 14ga straight makes a stiffer wheel and that's the way to go. Others say that double butted 14/15 spokes absorb stress better and produce a more durable wheel, and it would be lighter. So what's the answer?

Also, if I had to choose between DT and Wheelsmith would one brand be preferable over the other for a heavy duty wheel?

And what's the difference between using alloy vs. brass nipples for this kind of wheel?

Thanks much!

14/15 spokes and brass nips will suit you just fine.

we use wheelsmith spokes at my shop, and i've never had a problem with them. i'm actually in the middle of building up a new set of race wheels (road) with wheelsmith spokes, light & aero.

the double butted spokes are more durable for a couple of reasons.. 1) the 15ga part in the middle is a little more springy, it'll handle shock & vibrations a little better, 2) all that shock and stress is directed to the 14ga parts at the ends of the spoke where the spoke can handle the stress a little bit better.

brass nipples, well, i'm a bit timid when it comes to aluminum nips. i've replaced one too many cracked/rounded al nipples to want to put them on my own bike. someone of your weight (no offense) is going to be putting more stress on a wheel than a flyweight, so the extra durability will come in handy.

I have used Wheelsmith and DT in the past. They are good spokes however I currently reccomend Sapim spokes, they are superior in many ways to the other two.
Hey they are good enough for the USPS so they are good enough for the rest of us right?

Either will work, you will hardly notice any difference. The key is to keep your wheel true and spoke tensions even. I prefer brass nips. 250 is not that big, a friend of mine is 6' 6" and pushing 290 and he flies. The bike he rides is so big it looks like it belongs in a circus act hehe..

XT hubs and 519 rims should be fine for your weight, provided you go 36 spoke,Brass niples and DT straight gauge spokes. This is what my mate runs and he is around your weight. His last set of wheels were LX hubs and have finally needed retrueing after 15 months. I wish I could get my lightweight wheels to last this long, and I only weigh 150lbs.