ILuvChubbyChix:
Try using button style suspenders (braces in the UK). Forget about the clips. Clips either never grip properly, or are so rough as to wear out the waistband (primarily the more industrial/lumberjack type of clips). Buttons are the only way it'll stay connected reliably for hours, or weeks/months/years on end.
It's pretty easy to sew on the buttons. You'd want to sew the buttons on the inside, since on the outside looks very strange in this day and age. Now, locations of the buttons:
In the rear, about 2-3 inches on either side of the rear seam.
On either side.. you have one button that's about half an inch away from the side seam, towards the front. The other button will be on the waistband, above wear the crease would be, if you did crease. It doesn't matter whether you crease or not.
You should try to keep to these guidelines as long as possible. But, I suppose it's possible that beyond a certain very large size, you'd be forced to eventually deviate from these guidelines, since you can't really have each pair of buttons be farther than 6 inches apart. If that happens, find the midpoint between the two points I mentioned earlier, then 3 inches from either side of that midpoint.
I hope this helps. Correct button placement seems to be partially forgotten by the population as a whole, so hopefully what I said is helpful to someone.
Wow. Thats a wonderful post with some very useful information on button placement. I agree entirely with the clips being useless in the longer term when under the sort of strain we are talking about with a nice big belly!
