I'm using a modified Wayne Galligan technique. I took this picture from Bob Pastorello's website,
www.rcaerobats.net. I don't know if he drew it or if Wayne drew it, but I wanted to give credit for the original picture, as I took it and modified it. With the smaller wheelpants that we're using today, I actually use 2" DuBro foam wheels, and I fly off of rough grass at my home field with no issues.
What I do is take my wheelpant and figure out the inside width. I'll subtract the width of the wheel that I'm using, and give myself about 1/16" fudge factor. I make some appropriate thickness discs out of plywood, I've used both light ply and aircraft ply. Generally this works out to be around a 1/8" plate for the smaller wheelpants that I use. I drill a clearance for a 6-32 screw in on, and a clearance for a 6-32 blind nut in the other. Glue the plates into the wheelpants, with the blind nut end towards the gear leg, and put the blind nut in after your glue is dry.
Get an appropriate length 6-32 screw and thread it in from the outside of the wheelpant. It will pass through the wheel and go into the blind nut and into the gear leg. Put a #6 washer on the backside of the gear leg and a lock nut and you're in business. I don't even use a anti-rotation screw, as it's not necessary and I like to keep things as simple as possible. Alternatively, you could thread the screw in from the back side of the gear leg, and instead of having a clearance on the outer disc, drill and tap a for a 6-32 screw. You have to be a little more careful with this method; first, it's a little more involved as you'll need to cut threads all the way up to the cap on your screw, and you'll need to have a pretty exact length so you don't go through the outside of the pant. Also, you need to ensure that your wheelpants are strong, because if your pant splits down the seam, you'll lose the wheel.
I use this technique for several reasons. First, I hate axles. They're a pain in the ass, and it's always difficult to keep up with collars, or even the NMP axles with the locking 'C' ring, it's just something to lose and keep up with. Axles, especially the NMP, or MK ones, don't support the outer side of the wheelpant, and that's where you get a lot of broken wheelpants from them flexing so much. I don't know exactly how much this weighs, but it's just as light as anything else out there, you don't need to order something from Central to make it, I go to my LHS for the wheels and 1/2 mile down the road to the Ace Hardware for the screws. It's easy to make, easy to replace, and dirt cheap. I also think this is the surdiest way to mount wheelpants, and it definitely is the simplest for me.
Anyhow, that's my contribution. Remember, it's worth what you paid for it, but I highly reccomend it.