colonoscopy pres for s/p bariatric pts

Hi, we are a busy clinic gi suite and have recently started to see more bariatric pts in our practice. These pts are usually lap bands or Rue n y's.
We are seeing them for both problems and now for screening. Our usual preps for colonoscopy include either Colytely, miralax, or Halflytely preps with ducloax and without reglan.The Colytely and Halflytely pts are on one day of clear liquids the day prior to procedure. Miralax pts do one day full liquids then clear liquids on day of prep. We are concerned about the amount of fluid that a bariatric pt may have to consume and the effects of one of these preps along with the clear liqiud diet the day of the prep may have. Does anybody out there have special requirements for these pts.? Are there special reccommendations, or do we treat them as we would "normal" stomach-sized pts. Any info would be greatly appreciated. Thanks