HMMMM.i just read about this wonder soil. it is an expanding coco coir based soiless medium. it is enriched with all natural nutes that are supposed to last from seedling to harvest. No sir, I just don't like it for myself.
I am sure this product will grow cannabis. But, it seems like a MG product to me and I prefer to know what and when I am giving my gurlz...just the control freak in me.
Anyway, I am of the opinion that topping time can be anytime the grower sees fit. I topped one of my current gurlz after 6 days and the second after 8 days. I had all sorts of people telling me it was way too early, that it would stunt their growth...one even said I may as well dump them and start again....they are both very healthy and have been topped multip;le times since.
However, all that being said...my immediate thought for you is to transplant to a much bigger and better mixed medium. If you do not want to change mediums I would suggest adding about 30% perlite to the wonder soil, wait a week to 10 days to let her recover from transplant and then top.