Nice first grow so far Alex, Not sure how much I can help since I never grew in soil but I subscribed:clap:.
The only thing I would like to point out is about your candle comment. You're not producing Co2 with candles:sad:
CO (Carbon Monoxide) is produced with fire that emits a YELLOW flame...
At the flowering stage anything you do could considerably stunt bud production. That said I would top the one your having issues with as far down as it takes so the healthier one gets full light. This will possibly stunt it a bit but should be worth it if other can take advantage.
you should trim up the foliage some, to many leaves fighting for light(start with ones on bottom). I would also find a way to get a bigger container for roots if possible, looks like buy mid flower they will be choking each other out.
Thanks for the thread!