Might not be the most beautiful repair, but it’s on the butt so who cares? Well done!
I had one horse who always had to have the bungee tail cords. On Horseware fly sheets especially (that are very long) because he would hurt himself catching a leg in a nylon one. He loved to roll and lay down to sleep a lot. I find the coated bungees to be very forgiving.
EXCEPT last year when my horse’s neighbor decided to keep trying to eat my horse’s stable blankets and Insulators through the bars. I found a few of the tail cords in neighbor’s stall. Most of the time they were intact or I could pop the end back on. I think he destroyed one. Somehow did not actually destroy the blankets. I did have to change to the little tie on nylon cords for a little bit because those weren’t as fun to eat? Horse moved away, and so I went back to the bungees this winter.
Any chance your horse is getting help in destroying his tail straps?