Well, I would not recomend cutting the tail. Wow, if someone came into my barn and cut my horses tail, omg.. I would die.
Anyways, My horse is a TB but she has an unusualy long tail. It drags on the ground if I don't have it braded. In the spring, when its muddy, I just braid it up. I take it out each night when she is in her stall and rebraid it each morning before I let her out to pasture. In the winter I braid it and wrap it to keep the snow and ice out of it. I use vetwrap to wrap it but Im sure there are other ways to go about doing this. As for the mane, I don't have much expierance there. You see, I ride hunter style so my horse has her main pulled all year round, her mane is only about 3 or 4 inches long.
Well, I hope this helps a bit. :)
My Rambling T