It depends a lot on your further treatment and the grade of maturity you prefer (cloudy? amber?). If you are going to manipulate her (bending, pruning,...) even more during the grow, she likely will take 95+ days from sprout to be mostly cloudy or cloudy. Mine is topped and I applied a way lighter LST than you and -based on my experience with this strain- I estimate that she‘ll be ready after +/- 82-85 days (no amber).
BTW I don‘t think Forum Stomper was a good choice to be grown in such a small space like yours. Giving her enough space, she‘s absolutely wonderful! One of my Mephisto favorites and definitely a keeper. But IMHO she‘s too big and branchy for your needs.
Good luck and happy growing!