Wow, the whole project looks amazing! Every choice you made sounds like the right thing, from the staples to not trimming the fencing, to not ripping the 2x4s - you could re-use those in the future as well.
Thanks. The plants are starting to climb the trellis, so I'll have to post some pictures later in the summer. Looks like the trellis is working.
Someone mentioned that I should use stainless steel Arrow T-50 staples, because the normal staples will rust out and fail in no time. I checked into that option at Menards, and they do sell stainless steel staples that are T-50 compatible but made by another brand. But, holy cow, a pack of 1250 qty stainless steel staples costs $12.00 compared to $4.00 for a pack of 1250 qty regular T-50 staples. Depending on how long my regular staples last, I might just shoot in some more staples if/when they fail. If I see the staples failing within weeks, then I'll be looking at spending more for the stainless steel staples.
Or, if the staples pull out before they rust out, I'll probably replace them with the much stronger fence post staples.
For now, the regular 9/16 inch T-50 Arrow staples are holding....
The only thing I can think of is incorporating a ladder into the design, to make it easier to harvest the multiple pounds of produce that grow on the top pallet!
Please make sure you show us a picture later, when your plants are growing over it, I can't wait to see!
My arch trellis is not half as strong as that, for sure I will be copying your design once mine fails in a few years.

Not sure what you mean about a ladder? The top of the arch is only 6 feet high, so I can easily reach any produce. In fact, I had Dear Wife select the height so she could reach everything if the plants grow fruit on top of the arch.
As far as the design, Dear Wife really likes the trellis. Since I made it out of 2X4's and 2X4 wire fencing, it should last many years. Big thing for me was that I just used long pallet wood 2X4's and old 2X4 wire fencing I had out behind the garage. My cost was free other than a few screws and staples.