Sleep is awesome.
I think it was Paul Anderson who said when he was training seriously, he did 3 things: train, eat, and sleep.
And then there was a bit about why stand when you can sit? why sit when you can lie down? More rest = more growth was his point, and he proved it.
I'm of the opinion that metcon can be upped easier and quicker than strength and mass, and that a focused mass gain approach for a month or so requires minimal met con.
If you have the energy to met con regularly, you're not lifting (heavy) enough.
"Morning, Putski eats it, noon, Putski eats it, night, Putski eats it. Putski loves!"