What do you do with your pack?

[blackbishop351]

Yeah...just get an oversized piece of bedsheet or something, wrap it around your pack like a cover, and get a rough sketch of the shape/size you want. I did that once before to make a cover.

[Dingus Khan]

ditto, i just finished mine. i used the dimension given on JJ's site, approx 50"X60" and it was pretty darn big. i don't think it'll matter though since if you really wanted to secure it tightly, you could easily wrap the bottom up under your pack and pull it up between you and your pack. might take up some slack.
it is good for covering up horizontally lashed ccf pads too, although who cares if they get wet

[Just Jeff]

What I am planning on doing is stuffing my pack with something to make it as bulky as possible and then take measurements and make an AIO that is more suited to my pack size.

I got the measurements for my first model like that. The GoLite Speed is a tall and skinny pack when the removable top pocket is on there, so I wanted to make sure it fit over it all.

Don't forget to put stuff in any outer pockets, too. A water bottle in a side pocket can really change how a pack cover fits.

Good luck with the project.