Focus looks good to me, collimation could do with some work though... it reminds me of my first C11 image where I thought focus was off, but inspected the collimation the following night and realised that it was out quite a bit...
Other than that, your guiding looks good, field of view is stunning! The OAG is the only way to go, otherwise you'll be struggling with mirror flop issues and all sorts of flexture problems.. I know I did!
Good work mate, Give that collimation a touch up and you'll be producing some fantastic work..