When should I top,how long more my pots are ok?

[DaTrueWhiteMa]

Hello,my plants are 19 days old,they were getting not enough light for first 9 days so they might be little smaller,anyway.Guys how do you count nodes??? I want to top,but I dont know when,because I dont understand how to count set of leaves?? Ok nodes,is the part where from stem 2 side stems grow out is nodes?,ok but how to count set of leaves? I need to top around 4-5 set of leaves,here are pics.Btw I want to 4lst and then scrog.
1.How long more ~ this containers will be enough,its about 4 liters aka 1 gallon.
2.How to count set of leaves? Last picture is closer look,they are so short,this is why I dont understand...

 

[Mike Wright]

The largest of those plants could be repotted any time. It's good that they are short, the nodes are nice and tight. Looks like most of the girls are starting their 5th node (leaf set). That's a good point to top if you want, depends on your training plan. I lollipop the lowest branch set so if I top at the 5th node I have 8 main branches that I make into one even canopy.