Not sure about the placement of the inserts, the one on the right looks too far in for me and so the composition looks lop sided. I don't know if there are any 'rules of thumb' that might help here.
Lovely scene though - I love the bokeh snow flakes in the left insert.
I really really like the idea - I just wish the focus on the main panel was tighter on the silos (or is it an unavoidable function of the crop dust, making it look noisy?). Then again, my girlfriend prefers it the way it is, so of course I now think that I do too ;-)