Questions about PUL

[newdsmomma]

I can't seem to sell my girly trainers to fund new trainers for my boy, so I've started playing with sewing my own. I downloaded a couple free patterns and have been sewing by trial and error (lots of error!), so I thought I'd come to you ladies for advice:

1. When folks add PUL only in the wetzone on knit/cotton outers, how exactly do they do that?
I'm using FOE and have some scraps of PUL that I want to put to use, but don't know the best way to add it to soakers to minimize leaking. I know it won't be as waterproof as an entire PUL outer, but how do folks keep down the leaking/wicking?
Do they just sew a PUL backing on the soaker shape? Do they sew the PUL to the actual cotton outer? Does the colored part of the pul face the inside of the outside material or the opposite?

2. I'm considering buying the Tinkle Time pattern (after lots of trial and error and adapting the freebies I have with varying degrees of success), but don't really understand how wings of knit without PUL don't wick?
I love the idea of the stretchiness (the trainers I've made with PUL all the way around are a little tough for my little one to get on and off himself since they don't stretch as much), but can't understand how the inner absorbant layer doesn't wick right onto the wings.

3. How exactly does one apply FOE and is there a formula for how much to use at the waist and legs based on your child's measurements?
I've made some converted prefold trainers that are working well, but I ruined several pieces of FOE and a couple prefolds before hitting on something I can't find explained anywhere. When using FOE with all the layers of prefolds, it seems that you can't sew over the FOE while it is stretched or it doesn't gather much (all the instructions I could find said to sew while stretching). I found that instead, I need to stretch the foe on the fabric edge, hold tightly to the fabric encased in foe a couple inches out, then release the FOE, and sew over the already gathered fabric without letting it slip out of the FOE (which isn't easy!). Is this right? Is there another way?

Sorry for how long this is, but your advice and expertise will be greatly appreciated.

Thanks.