Growing Out Mane

So I have aquired a 11.2 HH Cob/Haflinger Pure white pony, he has an amazing mane theres just one thing wrong with it...the minature pony he was hoarded with decided to chew sections out of it. A lady rescued him and I am currently leasing him becuase she has no time to even come out to the barn. Now to the point, my old trainer told me (she keeps her horse at this barn) that if I put M-T-G in it and keep it braided that it will grow out and than to take it out for one day every week brush it and than put the braids back in. I have never heard of this and I was wondering if I could have your guys opinions on if this is a good method and if not do you have any other ways that might help? I don't want to do it this way and then his mane look like crap becuase the mane he has is gorgeaus!
Thanks!!

I've never used M-T-G, but keeping a the mane up in a braid will help to protect it from further damage. My horse came with a beautiful, long mane and I keep it up in a running braid because otherwise it turns into dreadlocks

I just started using M-T-G on my horse's tail with the hopes that a miracle will happen :) I will be applying it once a week as close to his tail bone as possible.

That being said, M-T-G is pretty miraculous at clearing scratches, rain rot, girth itch over night and the bottle says it helps with hair growth (up to 3 inches a month, so it says). So I'm figuring if it works like it said it would on skin conditions, there's a fair chance it will do wonders for hair growth (fingers crossed). Fun fact: M-T-G smells terrible and make sure you wear gloves when you use it, otherwise your hands smell like burnt sulfer and wood. Also, make sure you get it as close to the roots of the hair as possible instead of the actual strands of hair (you might want to do a small skin test to make sure your pony doesn't have a sensitivity reaction).