Looks like twill tape in the photo.
If so, haven't seen any specs on breaking strengths of twill tapes vs. Grosgrain.
But comparisons might be pointless, there being so many types of tapes and webbings available to the large manufacturers.
The original Hubba had nothing so fancy, just triangular patches sewn on. I did a silnylon fly for one and glued the patches on with GE silicone glue before sewing the panel pieces together. It came out quite well, with no sign of delamination. Used a roller, but did not clamp, as recommended by the article on BPL.
Noticed that all the tapes and buckles on the original Hubba fly were very well made and light, moreso than the stuff available from the MYOG suppliers, so borrowed them for the sil fly.
Considering the information provided in your theads, I think I will stick to semi-circular patches from now on. If you're bonding and not sewing the circular edge, there is no added difficulty. Because the glue has some 'creep,' I think that may also add a little to the strength before reaching the breaking point.