Winter tail braiding/bagging

So, I want to grow my mare's tail out over the winter. And I'm doing this thing where I'm going to keep it braided for a week, then unbraid it, brush it and put MTG in it, then rebraid it. I'm afraid that it's going to lead to breakage because it's being left in a braid. IS there maybe something I could put in it before I braid that will help keep it from breaking?
I know ShowSheen is no good cause it dries their hair out really bad. I have ManeN'Tail "protein enriched braiding spray" is this good for it?

If you are putting MTG in it, why would you put somethng else? Frankly, I braid mine in about January, and leave it about 8 weeks, but that is for mud and ice, not really to grow it out, as such. Mote of a protective measure. I use showsheen **gasp**, braid it tie it up just short of the bone, wrap it in Vetwrap and forget it. We do this for all the horses at our barn. Works great.

I have seen horses tails mildew when left in vet wrap too long without attention. I wash with shampoo, put a creme rinse in, dry it well and then braid. I tie it up with cotton strips braided into the tail. If I cover it with anything, it is with a cotton tube sock that breathes and will allow air into the braid.

I take the braid out every month and shampoo, creme rinse, dry and rebraid. You don't have to get the horse wet to do this. I wash and rinse by holding a bucket of warm water up and dunk the tail in cold weather. It is essential that the tail is dry before you braid it again. I use a simple blow dryer for this.

This is how I do it and I get very good results.

Could you explain how to do that? My riding instructor told me how before, but I still don't understand and I'd like to try it