Butyl Tape vs Polyurethane caulk

I might.. Just might get to the point where sanding, sealing and covering is done this weekend and I am considering my options for final install of my doors and windows. None of my windows or doors will have any screws or holes through the frame or wall, all are RV premade units and attached from the inside.
My options for exterior sealing of the flange to the camper wall seems to be butyl tape or caulk. The camper will be gray, and I used to use a gray polyurethane base caulk for our company trucks with camper shells. When a new door or opening had to be installed (these were big pest control trucks with camper shells or custom bed enclosures) I found the poly caulk held up to the daily grind of driving and weather, as well as the employees who were constantly opening and closing the doors/windows at every service stop.
Could In use a gray polyurethane to seal seal behind the flanges of the doors/windows on my camper, or should I order some butyl tape?
Neil
My options for exterior sealing of the flange to the camper wall seems to be butyl tape or caulk. The camper will be gray, and I used to use a gray polyurethane base caulk for our company trucks with camper shells. When a new door or opening had to be installed (these were big pest control trucks with camper shells or custom bed enclosures) I found the poly caulk held up to the daily grind of driving and weather, as well as the employees who were constantly opening and closing the doors/windows at every service stop.
Could In use a gray polyurethane to seal seal behind the flanges of the doors/windows on my camper, or should I order some butyl tape?
Neil