This is week four. I topped her last week and have...

Nah dude, I dont think its worth it with auto's unless you have a lot of time and some luck. You can see it on my grow, I topped during week 2 and 3 I believe and it's taking ages to flower :( start adding the Bloom when the stretch begins, bit by bit, but keep the amount low until the stretching noticeably stops. Then you can add more to help it flower. Also continue to add Grow until stretching stops to ensure max growth during this growth-spurt. However, if you want to finish sooner and have less stretch, then use less Grow. Just remember not to switch too abruptly to Bloom,go easy shes a living thing :D