Regrowing Lettuce

About a month ago we started an experiment to regrow romaine lettuce. Since then some commenters have asked what they look like now, so here they are.
lettuceRegrowAfter

roots

roots

What do you think? Kind-of interesting how 2 have grown so tall and the other is still short. The only explanation I can think of is I left 2 on the counter over night before putting them in water. But since I didn’t keep track of which 2 that was, I’m not sure that really explains the difference. Otherwise they have all sat in dishes with water, all next to each other under a grow light.
I want to chop the small one to eat and see how it grows back, but we plan to leave the tall ones alone to see if they will go to seed.
 
So do you have any experience regrowing lettuce, or any other food for that matter? If so, I would love to hear about it!
Happy Gardening! :)