I've never used it but you shouldn't need to double it-- unless you want an uber thick, super bulletproof soaker. It will work great on its own-- just make sure it's not superwash!
I've used it for one soaker and am working on a 2nd. I got the cascade 220 paints in forest and meadow. I found them to be very saturated and dark. Hard to knit with unless I have a lot of light. And the colors bleed a bit onto my B4s, but it seems to come out in the wash. I would still recommend them.
They're great for woolies, but they do get a bit pilly (I've made 2 pair of longies). It's cheap and it does come in great colors! And it's pretty soft, as Glad said. We don't use them at night, but they work very, very well for day.
Warning
No formatter is installed for the format bbhtml
Re: Cascade 220 for Longies?