First of all, really great puzzle. Simple rules easy to grasp, levels that have just one solution most of which need careful thought.
However, I'd really appreciate any hints for level 6.
I think the approach is to get green to the right by going over blue, then get blue on top of green by raising it on the left. Mostly because I can't see what else to do. However I can do the first part but not the second - Am I on the right lines, and either way any hints?