Good job with the cones - you adjust so there is a tiny bit of play. Once the QR is done up on the bike, it takes up that last little bit of play. Only ever adjust one side though - I make sure drive side is tight, and only ever adjust the non-drive side cones (personal preference).
I've just discovered that overtightening a QR can cause the bearings and/or freehub to bind. I pulled my rear wheel out on a climb a few months back so after that I tightened the Mavic QR to 'bastard tight'.
I was on a descent with bromptonfb last week and he noticed that my chain was being pulled round when I stopped pedalling because the wheel wasn't freewheeling properly.
A quick investigation revealed that the friction was so bad that the wheel would only do two turns and then stop if I lifted the back of the bike and span the pedals round.
I've put a better-gripping skewer on (Shimano) and have slackened the QR. There is much less friction now. Hopefully, I haven't permanently damaged any bearings. I'll see how I get on in today's ride which will be the first ride with the new skewer.
