I'm considering a bag with a Dryloft shell for cowboy camping. Would be using a ridgerest deluxe large or two under it but no groundcloth, bivy or anything. If I were to seam seal it how weather proof/resistant would it be? How would the fabric cope with the ground if/when hanging over the pads?

what's "cowboy camping"?

Sleeping under the stars. No tent, tarp, etc. Just me, my bed-roll and the elements.

If done without a ground pad it's called "brokeback" cowboy camping <img src="/forums/images/graemlins/smile.gif" alt="" />

The problem with Dryloft bags and no bivy are that, if you get dew or rain on the bag then have to pack it away the next morning, the moisture will seep through into the down. It's really much smarter to caryy a lightweight bivy bag which you can pack separately. However, if it's just for an overnight trip then you should be fine.

Better atleast have a piece of canvas ground cloth, <img src="/forums/images/graemlins/tongue.gif" alt="" /> ifn yer gonna camp like a cowpuncher...

You could rip a UL bag on the ground unless yer sleepin on snow. <img src="/forums/images/graemlins/shocked.gif" alt="" />

Seriously cowboys probably had more padding under them than your compressable bag will offer alone. Carry an extra wool horse blanket just in case... <img src="/forums/images/graemlins/grin.gif" alt="" />
<img src="/forums/images/graemlins/blush.gif" alt="" /> <img src="/forums/images/graemlins/grin.gif" alt="" />Jim <img src="/forums/images/graemlins/cool.gif" alt="" />

I have a bag with a dryloft shell and I like it. Here is a link to another thread that discusses the subject and to a post I made containing a condensed review of a bag with a dryloft shell.

Within reason I think a dryloft shell will do what you are looking for, it will protect you against heavy dews and frosts. I have never had mine in a rain nor do I intend to without some other form of protection.