there is no need to wait any length of time after topping to flower your plant,
it all depends on how big and what shape you want the plant to end up in what strain it is , how big do you expect it to get
you could top a plant at 10 inches put it straight into flower and it will still end up 4ft tall i have a plant like this growing at the moment
some people hold the false belief that topping the plant causes stress and you need to wait for the plant to heal or your plants will change sex or some other nonsense
Dude.......love the avatar!!! I like to grow mine to 8 full solid nodes, and cut the top there, making sure to only take the upward growth, NOT the two leaves on either sides, those will be the new branches. I let those grow, and get the total height to around 24" for my setup. I flip the lights, and cut off everything below the top 4 branches. I'll tie those out a bit, tie the top two in the opposite direction, and train them to make an upward circle. I let them keep going in flower, cutting off all the small stuff on the 4 main branches that aren't getting great light throught the grow, as well as any big fan leaves that are in the way of the buds getting light. I end up 4 big fat colas, and a bunch of nice fat nugs to boot. Any popcorn is cut down, dried, and trimmed a little, and just used for butter and BHO, and tincture. You'll get every bit of 4 zips of that strain per plant, if you have big lights and co2 like me. No prob!
i dont like to top my plants , i would rather bend them into a sea of green. any trimming will stunt the growth and may cost you 3 or 4 days of your growing cycle. i only grow for 10 days so 3 days is a big piece of my vegative stage .