Best way to train to gain lean mass

[super.muscle3]

I can train 6 times per week, so I wonder if the best way is to train a single muscle per day, or two muscles perday 3 times a week.
Or even it could be two muscles per day 6 times a week.

Another alternative could be all the muscles in the same day, 3 times a week, so all the muscles have 48 hours rest.

Opinions?

 

[FAMAS]

I'm not a personal trainer, but from my experience in fitness, including Gym, Boxing and ended up with being my own persoanl trainer at home *lol* I'd suggest, train 3 times a week, 2 muscle groups each day, with short sets and big weight to increase Mass as you say. And either you rest in between days, or go for a quick cardio Run

In any case, say the days are Mon to Sat, Sunday get a proper rest, no exercise at all, it will replenish you But don't eat like crazy that day *lol* That's my temptation on rest days xD