Topping an autoflower is a gamble because there is no recovery window before flowering starts on its own. Low stress training with soft ties gets most of the canopy benefit without pausing growth, and I only try anything more aggressive on strains known to stretch a lot. The write up on training methods at https://turboautoflowerseeds.com explains which techniques are safe by week and which ones tend to leave you with a stunted runt. Gentle is the rule for the first three weeks.