Laxative rebound effects? Miralax?

I'm going on a trip next Saturday and I wanted to do a total clean out in the next couple days so that my digestive system is better for it (I have IBS). Had a colonoscopy a month ago and was thinking about doing the otc version of colonoscopy prep (Miralax in Gatorade). I've used senna tea 4 or 5 times and the last time I used them, 2 weeks ago I had what I felt was rebound constipation after. I would much rather avoid this while I'm traveling and I can't figure out if there is a risk of rebound constipation from Miralax. My understanding is it is osmotic - pulls in water - not physical like induces peristalsis, so I'm wondering if it is less likely to have that rebound effect (I didn't feel like I had one after the colonoscopy prep which was also osmotic but I had never ever taken a chemical laxative before). Any thoughts/experiences? I would love to have the clean out effect but definitely want to avoid followup constipation if at all possible.