Make walls thinner on object?

[Bassna]

Yeah, I figure the problem is the walls on the model are too thick. If I change it to 1 outer perimeter shell, it's still doing 2 walls with a single shell. I want to get it down to a single wall, I'd prefer to do with 2 shells, but doing with 2 shells is currently doing 2 walls, and 2 shells, which takes a substantial amount of time more. I believe the problem is the model being too thick, that's why I want to thin it out. Other than trying Makerware I still haven't figured it out :P But using Makerware just is going to create more problems because I have a lot of customization in my prints.

https://i.gyazo.com/c73e98d453baa1f8...ea46986d97.png

For some reason my picture isn't showing up on here.