depending on the boots and the way you ride. I think custom wide is only a mid wide.
I have a custom x and it is narrower than other board. I have 164 custom x (252mm)(regular width) and i wish it was wide. when the snow gets soft there is some drag. I wear 10.5-11 size boots, but i liked to put the board on its edge at very high angle when i ride.
between 158 (254mm) and 162 wide (260mm) there is only 6mm difference. Is it a camber board? i think 08 custom was still cambered. 158 may not have enough float. I also have old lib tech emmagator and its waist was around 260mm and width wise it fit me perfect and so does my old dominant 159 (i think they are made to be mid wide with 260mm waist)
Size 11 is where you are in the middle of regular and wide board but since custom is a narrower board to start with i think 162 wide would be ok (its actually mid wide). 162w would be little stiffer too due to length and width. And it is not too long for your height and weight. Plus custom is mid flexing board
for buttering and small jumps 158 would be better.
for trees 158
for powder 162W
for charging 162W
You are going to have to decide which is more important to you. when it comes down to it you should be able to handle either length. More of a preference thing. I would pick 162W because it suits my style of riding better. 158 would be better when i am hitting park and jumps but i am willing to live with that since 162w would be more stable at higher speed.