Are there any tips that someone would be willing to share on trimming out innie windows? I will be placing 1 1/2" EPS foam over the outside sheeting. I'm thinking about vinyl siding or maybe even steel siding applied horizontally. Is there any advantage to purchasing the windows with J channel? I'm looking for all good ideas. Thanks

The J channel does make it easier, especially if you are trimming with drywall. If using wood you have to use 1/2" thick, because I think that is what the J channel is. Otherwise lots of the long shims.

If you get a window with J channel its part of the exterior nail flange. You can buy snap in drywall return for the inside if that is what you mean.