I use either MTG, Santa Fe Coat and Conditioner (with an SPF.. I mainly use that on Gem in the summer because he's white) and EQyss Avocado Mist detangler and conditioner.
I use the Santa fe and EQyss the same. I use it for both brushing out the mane and tail and also rubbing it into the tail bone or crest. I then leave the tail or mane.
When I use MTG, I put it in the tail bone or crest. For the tail, I do a loose braid and then vet wrap it. I did this with Vega and her tail grew in length and thickness. I have not applied it to any manes, but I plan to this winter to both Vega and Montana.
When I bathe them, I use Mane and Tail conditioner, but I always wash it out.