Thank you for your feedback. Thanks to
@TensorBackhand for his feedback too.
I am going to pass on Z2. I will stick with C-1 for now on my backhand (my forehand has always been H3 and i don't see that changing soon. I have a 729 Battleship II blue spone that just arrived 2 days ago from Aliexpress. I might try that on my forehand soon but I am not in a hurry). Then as my backhand progresses, I will go to G-1. Then at the next stage I will try Z2.
I am about 1700 in USATT ratings. The odd thing is I used to play penhold so I am used to blocking aggressively on my backhand. And I loved loved G-1. It was very direct. The ball is linear. It is fast but not too fast. The ball will go wherever you want it to go.
Then I switched to carbon blade, and G-1 is just weird. Then I discovered 2.0mm C-1 and I found out that I don't have to block on my backhand anymore. Looping from my backhand side against backspin or side spin serves becomes very easy! So C-1 and Rakza 7 soft at 2.0mm sponge are here to stay with me for a while. Now I finally have the confidence to develop my backhand loop which will be key for me to move up to the 1800-2000 range for sure. Thanks!