Personally, I would be waiting a bit longer and let them get a good root system going before adding any stresses to their lives. I usually wait until 6-10 nodes and until I can see branches growing first. That is the point of LST after all, training the branches, so manipulating them before they have branches just seems like a waste of energy and unnecessary stress to me, and they probably don't need stress at this young age/size.
Talking about root systems, next time you grow, your plants will benefit greatly by having the pots filled right up. This will provide much more room for root development which translates to much more above ground growth, plus it does not take up any extra room in your grow space. It is also easier to keep your plants hydrated, especially when flowering and it also lessens the risk of nutrient salts building up in the substrate. Your plants will also benefit from the increase of reflected light reaching the lower parts of the plant, light they can not get as they are now, due to being behind the "wall" of the pot.
This seems a common occurrence in this forum and I don't understand why. After all, everyone wants to grow the biggest and healthiest plants they can, then they only half fill their pots, limiting their plants potential growth. Quite odd really. The substrate is usually the cheapest part of the whole grow, yet people seem to economise with it. Anyway, each to their own, I suppose.
Hope this helps you or anybody else who might read this, and yes, I am feeling a bit philosophical today!
Cheers ......... Organoman.