I think the most significant difference in the two rounds so far is the internodal spacing.
First round the spacing of the first 5 nodes was approximately 1"-1 1/4" and then they started to spread out
Second round the spacing of the first node is 1" and then they gradually increase in spacing.
These plants are within an inch of the finished height of the first-round plants, the first round is about to be harvested, and they are looking like it will be bountiful. I think this round will prove to be even more impressive. the base of each of the plants is 30% thicker than the first round as well. Soon they will have the space to themselves and be able to use all of the available light.
I will get better pictures next week. Fed with Humboldt's Secret Base A+ Base B + Golden Root + Tree Trunk + Flower Stacker + Sweet & Sticky + Plant Enzymes based on HS schedule week 2 flowering.