The one part glue is for emergency repairs. I would only use it for temporary repairs. Use the two part correctly and you will get a very strong bond. here is a link to proper PVC gluing techniques. Hypalon instructions are also on this website, see the links at the bottom of the page.
Often you can just pull the edges back with the accessory, use a thin piece of wood to prop up a bigger flap or if necessary use a thread and needle. I have used thread through the material on non tube repairs to keep the edge open and the small hole just seals up when the material is bonded.
You should always pull on seams around an unbonded area to see if the open section will get bigger. You will often find the surrounding bond is ready to fail. It is disheartening to extend an open seam, but better now than later!
The floor to tube bond is very important. Be sure to clean and properly prep the surfaces to be bonded. New glue does not stick to old glue. I repaired my floor to tube seam with the tubes inflated. This seam takes a lot of abuse. Be sure the humidity and temp are within the acceptable range. You want as strong of a bond as you can get!
Using the thread technique: