Honestly I'd go with a thinner material for a pullout personally than 500d unless you needed a really hard wearing one for a specific purpose.
Yeah the 7x4x2 pocket will fit belts with PALS as a base design, mounting noted below to fit belts that are 1" between rows of PALS and also belts that are 2" between rows of PALS. If making some other custom size I just need to know the H1, H2, H3, W1, W2 dimensions on the sketch.
I can also do a channel on the back of the pocket to put a strap through like I'm told EXO packs are set up for instance.