transplanted from 1 gal to 5 gal about 10 or 11 da...

I wouldn't be worried about filling your pot with roots, worry about filling out your canopy. Time your switch to when the footprint is ready. Roots are gonna do what they do, if your plant is growing bigger you can bet the rootball is too.

Hey there you can flip to flower whenever now. Plants still male.a good amount of roots durrimg early.flower so it's good to have room for the roots to grow. Also you could let them grow just a few more days and bulk up just a bit more. Just remember the plants will get alot larger the 1stn3 weeks flower

10-11 days is plenty.. minimum 5-7 is probably okay. What modmyplants said is a great way to measure readiness too. How fast are they drinking down an irrigation? As long as it isn't many days, that means the roots have colonized the pot fairly well. If irrigating every 2-3 days with a healthy dryback, it's well rooted in new pot. YMMV on this a bit based on how the substrate is constituted. What is a normal period of time between irrigations for you in a 5-gallon pot? That's your target (a "normal" irrigation cycle) and a bit shy of that is fine as it's just a matter of days before the roots catch up at that point, too. As far as maximizing space... if current total area of plant canopies is roughly half the tent's space, it'll fill in barring major issues.