There are several different seatback heights that were used over the years. The high back is shoulder height, while the 'standard' is mid-shoulder-blade and I think there is one even shorter. Some of the seat meshes had a pocket in the top, some didn't. I think RANS used buckles to fasten them for a few years, but they didn't hold tension very well. Zip-ties worked best. My mesh uses 8" zip ties, paired at each hole.