Alas, did not find any new and better adhesives. The Hysol U-09FL remains the champ. That one, and some of the ones used by Steve Evans in the tests in his video linked above, are very pricey, so did not fork up for a 3M urethane adhesive.
The Hysol did confirm the weakness of DCF on what appear to be weft threads. Those threads can separate, and when enough force is used to pull bonded pieces apart, the mylar sandwich, which is very fragile, can rupture.
But logically, the tie-out patches, if large enough to disperse forces, can be bonded with their warp threads perpendicular to the weft threads on the base fabric. The Hysol bonds are very strong, and will rip the mylar sandwich right off the weft threads if enough force is applied. So a large enough patch, with its warp threads running at right angles to the weft threads on the base fabric should deter this.
I found the half oz/yd2 DCF a bit too much like tissue paper, but rummaged about and found a roll of some old light green Cuben weighing .65 oz that was much more opaque, and might work. But think a smaller second patch, along the lines of Brook’s post on the thread that Stumphges linked, perhaps even diagonal to the warp and weft of the base fabric and first patch, might be strong enough for sewing on some tapes to attach to tie-outs.
But if the DCF is to be used for tent doors, bonding to beak shaped DCF door panels will be necessary, not to mention zippers on the doors. No surprise that Zpacks tried other methods for securing doors. At some point, DCF reinforcements and/or tapes may simply become heavier than the weight savings from the DCF base fabric.
Before going there, some more time will be spent with Porcher’s 29 gram paraglider fabric. It is 6.6 woven nylon with double ripstop squares and a PU coat, and may be more resistant to expansion and sag due to water absorption than silnylon. It also might keep just enough bias stretch to tautly hold a tent framework in strong winds, and of course would be more friendly to sewing. Or all this may be the stuff of dreams. Have some additional paraglider fabric coming from one of Extrem Textil’s competitors in Germany. The first to know will be you if the dreams come true.