X2... Call Brandon at Avid for your sliders man. I beat the living hell out of mine, and he'll do whatever setup you request. I have DOM outer tube, square tube inner hybrids with kickouts welded on.... Feel free to come inspect my truck to see that they work
Also... go welded on man. Don't bother with bolt on. If it's worth doing, it's worth doing right. The less holes you drill in the frame, the better integrity you'll preserve. Plus it's stronger... and if you ever wish to remove them and "revert to stock" it's much easier to get it looking factory again cutting/grinding/painting them off.