I am running my first ever grow x4 auto flowers orange sherbet from fast buds in 12L fabric pots have been performing LST since week 3 my question is when should LST be stopped or should it be stopped at all ... today is week 5 so signs of flowering has started I will introduce bloom nutrients

When the plants stop stretching around day 21 of flower is when most stop LST. I personally sometimes do supercropping to help maintain an even canopy so it doesn't have to just be LST for that.