Sorry your having all that trouble but I am pretty sure part of it is the shape of Daves boat. But without photos it's hard to know exactly what you ran into. If you were trying to end up with a seam only on the top of the boat as I did in the video that would not happen with the shape your working with. On my canoe which has more upright ends, I have to run a seam well down the stern. Same with the Curlews bow.

Every boat is different and the one I did in the video just happened to be an easier one. It wasn't to make it look easier! I am about to reskin a Curlew and now that you have said that I may film that and try to show how to do that. But sounds like you did what I do. Since the polyester doesn't stretch like nylon once I get near the end I start pulling it tight and deciding how it will lay on the boat and how I will have to sew it on.

For those not familiar with this fabric, it is a loos weave and if you try to sew it on like nylon, pockets on the end and pull it tight with the stitching you will end up a the biggest mess you have seen. It will look like a piece of Swiss cheese