Good idea to modify the original stock arrangement…
I didn't have toggles so I used some tiny cord locks I already had on hand and some 1.2mm zline, borrowing a technique that is used on the MLD Duomid.

I got to field test the door closure system and it worked fine. I could see how one could live without it, but it was useful for a 2:30am visit to the latrine, and I think it would be more appreciated under adverse conditions with wind and rain, when you want to get back into the tent and get everything battened down in a hurry. If you're careful and are not too physically large, and watch where you step, it is possible to egress/ingress through the slackened door panels without unclipping them. Admittedly takes a bit of practice, but I did just that.
I'm rather dubious that Zpacks will use my door closure system. However I would offer the observation that it would make life a bit easier if they reversed the LL3 direction so that the cinching action pulls inward vs outward, making it easier to manipulate from the inside where it is more awkward to reach it.