The tilting is caused by the plant leaning towards the sun and of no consequence. If you straighten her out now, this will cause issues with shading of the lower parts of the plant which have already adapted to growing in harmony with the upper portion tilting.
In my opinion, she still needs another 3-4 weeks, so don't get to eager to flush just yet. Wait until the pistils are about 90% brown before flushing and harvest around 95% brown pistils, this will give you flowers with peak cannabinoid quality. Judging harvest timing solely on trichome appearance has many traps and is not 100% reliable, as some plants never get amber trichomes, while others will have 75% amber trichomes after only 4 weeks of flowering.
Flushing does not need to be a long and drawn out process, it can be as simple as giving just plain water for the last 3 irrigations before harvest and there will be no noticeable differences between this and a flush that has taken 2 weeks and many litres of water unnecessarily. Unless you are using a product like Miracle Grow or something similar, then a 2 week flush would be critical, but who grows cannabis with Miracle Grow these days??
Hope this helps,.........
Organoman.