Transplanting 10 gal preflowering plant to 30 gal pot

Hey everyone, I just thought to open a new thread about this.. I have a big ass photoperiod girl that’s preflowering outside under 13-14 hours of direct sunlight, critically rootbound in a 40 liters fabric pot. She drinks more than 4 gallons of water every day..
She may flower in 3-4 weeks, when I plan to cover her every night for 12 hours straight..

Do you think that transplanting her in a 100 liters smart pot would be helpful? Will she grow new roots and fill the pot in that last month she has before producing blooms?
I plan to transplant cutting away the old pot to avoid stress and prune the roots just a little

If the plant is already root bound it's a good idea to transplant it before flowering. It's just going to grow even bigger during flower and will need more space for that growth and for producing the best buds. Good luck.