I have more fun when I dont top the chem's unless its a sativa lean then yeah i chop the top in veg before flowering.
I've run topdawg for a long time many of them. only tip I think of is feeding. less is more. a little more in flower and they fail, no nose, no proper finish etc. a real bummer for a beautiful line. the variegation that pops up comes with some weird habits too, I dont like them when I see it, mostly on tres gear....and finally concluded I've wasted some years and if I only would have had the TD Super City none other would have made the cut. At the time of growing know that I liked them all, and they were good, not knocking the line or breeders at all. they rose to the top of my room for some time..... as time progresses the cream rises to the top, better expression and effects may be found and that makes the others punk. lol
On Gu's gear I find no variegation and no strange growth patterns, no special treatment no weak plants. They all respond exactly as expected. good breed stock selection !
havent finished copper chem but with the facts i have I believe this is the ultimate chem 4 expression, if thats what one seeks. When Dynamite finishes I expect her to take a place here also. Jamoka is freaking me out, I honestly miss this pissy smelly skunk since my teens, its really ticking the boxes as she is about halfway through flower now. every day now she surprises me with some more weird profile, I'm loving the girl much. wish I vegged longer before sexing though...I have copies so hehe....my veg room is full of gu copies awaiting their donors to finish, be judged/culled/saved.
before gu's gear offered me promise:
No chems have outperformed my RD Commerce City Kush in the "Chem 4" arena. I purchased every chem cross at attitude/herbies/single and more cant recall and have finished them all several times. Chem's been my grow room stable from day one.
CCK beat all tres gear except super city, a strong equal, with better yielder, larger colas. it was a tough fight believe me.
above is my opinion and experiences. nobody else better not have the same ones ever. I dont sell seeds or work for anybody that does. I dont follow much of the advice given on this forum. my garden doesnt share many of the experiences shared on this forum.