26 in. x 12 ft. Polycarbonate Roofing Panel in Clear

Use the recommended 1 corrugation overlap and pay attention to adhering to the minimum pitch. Too little of a pitch will slow down the shedding of water and allow it (the water) to wick into the overlapped seams.

Install a fine tooth saw blade backwards in your circular saw. It will cut the material without chipping. Make sure the blade is a fine toothed one, like the type used to cut thin plywood and such.

#1, you are probably talking about a butyl tape sealant, which comes in a roll of 40 feet. It's cheap, and it's what Pros use to seal the edges of panels. It's not in every Home Depot store for sure, but it's super common to use this stuff. It is necessary to use this on any roof that is lower than 3:12. You might need it more so in heavy snow areas and where the underneath is unheated. Look for this at Home Depot: 1/4 in. x 40 ft. Butyl Rubber Sealant Tape Model # 40BT Internet #207149821 Store SKU #457389 (Or its equivalent) Use that butyl tape on long panel overlaps on low pitch roofs. Clear or metal. You then put in "lap" or "stitch" screws to hold the two adjacent panels together, mashing the butyl tape together, about every 20 to 24 inches. You should not use the regular Tek or metal roofing screws that are woodgrip and long. Stitch screws are 3/4 or 7/8 inch long. The end closures are a completely different component. They seal the structure to keep something mostly air tight and keep blowing rain out; they do not seal the roof from rain showers and gravity flowing water. Those closures are for sealing the building, and are sometimes left out, especially at the lower end (eave). The upper ones at the roof peak are more important for rain storms.

Hello Decked, glad to help answer your question. Personally I would have a 3 inch drop on slope over the entire length. Good luck with your project.