I used this tape, Super Seam Tape 9460PC - 3/8".
The seams hold up fine for normal wear but if you pull on them hard enough they will seperate. I did notice the seams got significantly stronger after hanging up for a week or two. If it becomes a problem I will do a proper seam and fold the edges over and retape.
I didnt do a proper feld seam, I think its called a feld seam. I was lazy when I taped it and just taped down the seam and stuck both pieces together. Then I flattened it out with a chapstick tube like applying a sticker. Anybody can make these! :)
I have not tested in cold and wet conditions yet, hopefully the adhesive holds up. I have tested it in 100 degree weather and heat doesnt seem to weaken the seam. I live near the Southern most trailhead of the PCT so we don't see this kind of weather often.