You can top autos...but definitely top the ones that are very healthy to begin with, then there's less chance of slowing it way down. The #1 thing that helped me get bigger buds on the autos was cleaning up the bottoms. Right before flowering and right after go through and pluck or cut away any budsites/branches that are gonna be the shady ones, and some leaves too.
Happy growing the plant looks great this week hope the calmag helps it out.✌️