Just my 2c worth but I'd rule out 50 for a start. 50J is not good at all with it being next to the loo and curtain.

I'd also rule out 56 as J is right next to the galley. Behind 59 is the WTP bassinet seats but rarely have I seen a baby there, usually the middle pair in WTP. I actually like 59 K as its direct aisle access.

52 A and B are fine and I prefer the front CW cabin. Lots of various views in this thread and the Wiki too. It's always a chance waiting until T7 days somits all very subjective re paying or not.