Here are my thoughts
First off, just to make sure you know, the "X" means wide in both of these models. I have size 11.5 and i love riding a wide board, and would recommend that to you as well. I think your on the right track for length. So the choice becomes either the Heritage X 159 (the x does not come in 58) Or the Proto CTX 158.
Now that i am positive we are on the same page on that detail lets decide on the board. For what kind of riding it sounds like you are interested in, both of these boards will preform very well. However they are still each their own board. I own the Proto CTX 158, however i think for you the Heritage X might make the better choice. And here's why i'm leaning this way.
When charging through crud the Heritage is going to plow through with a bit more confidence. When riding pow the Heritage will also float slightly better due to being slightly directional. It will also feel more stable in high speed carves.
You might be asking what is the Proto better at? Riding switch, especially in pow is going to be easier on the Proto, being a true twin. Butters/presses are also easier. I also like the slightly tighter turning radius that is possible with a slightly softer board, and i mean very slightly here, but that just might make the difference between hitting that tree, and a close call. These are the things that made me choose the proto.
As a wrap-up unless you really want to get into riding switch and more park, the Heritage X will be (in my opinion) the better board for your riding preferences. And will still not let you down in the park by any means. However i would like to add, have you heard of the Never Summer Legacy? It is the wide version of the SL, and is in between the Heritage and Proto in most respects. That does come in a 158. And honestly that might be the best choice of all... But any of these three will do you great for your all mountain all condition board.