I had this problem in spades with my Tangerine Dream grow! I LST'd the living daylights out of her to get her to fit inside the tent - I was LSTing her two weeks before harvest!! This is really all you can do, to be honest. I had thought of unzipping the top off my tent and hanging the light from a beam above to give my ladies more room but the loss of light was too great. Pretty much all my stems had so many twists and bends in them, I couldn't figure out which was the main cola and which weren't ... the upside of all this was the fact that so much light got to so many bud sites, I had an amazing crop and many, MANY side buds were the same size as the main cola.
Contrary to what you might think, LST does not stress a plant out and so you can do as much of it at one time as you want/need to... especially in flower, an auto is going to be bound and determined to get up to that light and you'll see the movement within an hour or so of any LST you do to her. I like to use the clips they sell for LST which bends the stem at a 90-degree angle - just make sure you're using them on a fairly pliable part of the stem. I "goofed" and tried to use one a little lower on the main cola and it ended up being HST instead of LST... but even THAT didn't bother her... she was shooting up towards the light within 1/2 hour... So go for it... tell her you need her to stay inside the tent, please and thank you!
Good luck and enjoy the grow!