WakeWorld - Board Size!

Hey guys, so I'm sure everyone has obsessively looked for the right board at some point. I am having trouble figuring out what size board to get. I really don't have the ability to demo boards where I live either. I am 6' and 155-165 pounds, and currently ride a hand-me-down liquid force trip 142. I feel like the board takes me riding opposed to me riding the board. I pop off the wake and the board takes over in the air. I do like the edge control and the speed it has, and sometimes when I pop a good one its feels awesome. With that said, from what I've researched on here that I would like a LF Witness, but it only comes in a 136 and a 140. I feel like the the 140 may be too big again, but the 136 could be too small?

I'm jumping the wake both ways and doing 180s and grabs, and really looking to progress next season. I'd say the most important thing in a board for me is edge control, and I like the idea of the hybrid rockers (which is why the witness seems the best). Or maybe I should just get a 138 Trip?

Any help would be greatly appreciated!