Almost the end of week 10 and still no sign of flo...

It does say its an xxl auto strain and it is clearly stretching? You could always add a couple of small red cfl bulbs or red led strips? Just wait it out.

I could not find any information on the type of lights you are using. My suspicion, based on this diary and your other, is that your lights might be the culprit possibly having a blue heavy spectrum and not being intense enough. This would explain the strong veg growth, crazy stretch and weak flowering. Do you know what your ppfd at the canopy is?

Well to grow from a little tiny thing in your first week to now my god. That's a awesome bean there and yes I have seen this in a few grows here on the forum I just can't seem to remember there are so many journals . I mean if your nearing height restriction levels then you may need to do like you said and do 12/12 but they are autos so they will flower internally with there set clock it will help ..if they still gonna stretch like monsters maby suppercroping them and tiring down when cropped so as to not bounce right back up ..best of luck with the monster ...

I had to do this once with a white widow x big bud auto. I switched it at week 6 though. Not sure where switching it now will take you. If it's already almost 3 feet tall and you have limited space you could run in to problems. Maybe consider super cropping if you run into height restrictions.