My gelding has a very full and long tail. I actually just had to take 2 inches off it because he kept stepping on it when he stood up from rolling!
My typical routine is to brush it every so often [usually every 2 weeks, or so] and pick out any "large debris" when I see them [sticks/ plants from turnout, that sort of thing].
I never, ever, use anything on it other than a mix of coconut oil and jojoba oil [it's solid at first, I use a hoof pick to cut a chunk out, then liquefy it in my hands - you can also use a microwave to liquefy it]. A small amount goes quite a long way, I use a pea-sized chunk for his entire tail. I oil from the top and brush from the bottom - sometimes the bottom needs a bit more oil, usually not much.
I also trim it pretty regularly. Usually I only take a cm off, or so, but the act of trimming helps limit split ends and keeps the tail more free-flowing.
I used to bag and braid his tail to keep it clean, but I noticed that the tail bag seemed to encourage a lot of "whispies" at the top of the bag. I found, this year, that I was willing to let his tail be dirty in exchange for avoiding those whispies - other people might not feel the same! I'm lucky that his tail is pretty dark, I'd feel differently if it were getting stained!
He gets a LOT of vitamin E and fat in his diet due to his other issues, and a nice side effect of that is a strong mane and tail! He already has the genetics for strong, and long, hair so his diet only adds to that.
For my gelding, at least, mostly ignoring his hair seems to be the way to go. And not using silicones [Cowboy Magic/ShowSheen/anything with ingredients ending in "...one"] on it EVER. His hair quality improved greatly once the parts that had been siliconed in the past grew out and were trimmed off.
I actually had to completely roach his mane off 2 years ago due to how damaged it was from various silicone products.