I've been reading all the info i can find about proper basement insulation techniques including the building science report. I now realize that using foam boards attached directly to the foundation walls is the way to go. My probelm is that a friend and handyman already framed most of my basement before I did my research. I have a 1/2" to 3/4" gap between the foundation wall and the framing so my options are limited.
The room I framed is the middle cross section of an "H" shaped basement so there is only 2 walls that are next to the foundation.
Here are a few options i thought of:
1. Cut 2" thick foam pieces(or thicker) to fit between the studs and fill in the gaps with spray foam. then just drywall as is. (Is this enough insulation?)
2. Slide 1/2" foam boards behind framing and then add additional insulation between the studs - either more foam cut to fit like in option1 or bat insulation (however, this won't leave much of an air gap between foam and bat)
option #4 is your best bet. Anything else you do remember that making a perfect seal on the insulation against the concrete wall is critical. Sealing the joints with spray foam will work. Cannot address what size you need or if the insulation you mention is "enough" since you did not list your location in your profile.