Sizing for double-knit

[Knit4Pie]

I want to try a double-knit hat, and I'm trying to figure out sizing. Can I take a regular hat pattern and make it double-knit? Will it fit the same? I have a pattern in mind (kind of) and am wondering what changes I would have to make if the sizing changes...

[Mirl56]

http://alison.knitsmiths.us/pattern_..._knit_cap.html
http://www.knitty.com/ISSUEfall02/PATTdkhat.html
http://www.hjsstudio.com/doublehat.html

Here are a couple patterns.

[Knit4Pie]

Thank you, but what I want to know is if I take a pattern for a regular hat (or make one up myself) and want to make it double-knit, will the size have to be modified. I've seen patterns for double-knit hats, and none of them really do it for me.

[klymyshyn]

I believe that I've heard that you should make the outer layer only slightly larger so that the inner layer will not pucker.

[Mike]

Hard to say, your gauge double knitting is probably different than not double knitting.
I think I went with the same number of stitches as many hats (I was determined to get a good hat when I was learning how to knit) taught me were right and it came out a little large.
My DK hat doesn't stretch to fit at all, it could handle a stitch or two less. But it's also nice because my head doesn't feel squished after wearing it for a long time.

I believe that I've heard that you should make the outer layer only slightly larger so that the inner layer will not pucker.

That seems to be taken care of by the differences in gauge. Except it's my inner layer that comes out slightly larger.
But I can still use the inner layer as the inner layer, it kind of blocks itself right.