I try to have all diff auto strains on same height...

So basically you want an even canopy similar to a sea of green type grow? I would definitely try to grow similar genetics so that they all finish around the same time ie indica dominant strains will finish a week or three before a sativa dominant variety Topping LST HST and netting can all be used to help keep the canopy even Good luck mate

Se ve genial. Las puntas más altas puedes tegerlas en la red en forma orizontal Al final del estiramiento puedes podar las ramas que están por debajo del dosel para promover el creciento en los cogollos de arriba.

HST the tall ones after vege growth ends. there's genetic variety as well as changes in environment from grow to grow, if they consistently grow too tall, you should train them horizontally a bit longer on average before letting them go vertically. Start taking now the timing relative to the display of preflowers. this should be a fairly consistent method to time it relative to biological flip to flower phase. (flower phase started before you could see the preflowers, but that doesn't matter) if you have a suspicion a strain will be lankier than others, train it 5-7 days longer than the other plants... while still some fog of war, you get greater consistency within a strain with better breeders of photoperiods.

Check out my grow diary. I have two different strains there and have been able to manage the same canopy height. I did this by LST the entire way from week 2 on. I kept pulling branches down and in certain directions to develop a full and even canopy. They are now in their first full week of flower and the canopy is full and nearly perfect in height. I had to keep up on it and adjust every day but it’s worth it. Seriously 5 min worth of effort a day. I used electrical wire that were cut into 10” strips. A small U shape on one end to mount to the branch then I push the straight part way down into the soil to bend the branch and hold it. As soon as the plant was big enough, I used the holes on the pot to secure down to instead of into the soil. FYI, don’t top your auto, just LST the thing down and keep that main stalk growing as fast as you can. I hope this helps.