ImOnCrank, is a "flatkey" lock one of those American Locks or similar, the ones stores where recommending after the krypto scandal? Cause if it is it ain't safe, at least not in NYC. Had a friend who lost a bike using one of those. To add insult to it all they took the kyrpto chain with it. Chopped right through the big old American Lock, the ones stores use on their gates, looked like it took two tries with a big ass bolt cutter.

I go the chain + mini route as well, and always try and lock both wheels and also lock both locks to the pole. Best is when you can get the chain through both wheels and then just use the mini on the frame.