It is interesting that you liked hard rubbers on ZQ and I would really like to know how did you make it work. I find harder rubbers somehow difficult to produce spin, while it wasn't the issue on a different blade of similar speed. The arc is there, the unique feel like the ball is right there, glued to the rubber for a split second, is very prominent, and loops are easy to land, but the spin is just not there.
The worst of all I have tried was probably 39-deg Jupiter 2. Even when boosted, it just doesn't deliver the spin unless there is a very good brush contact. All while looping itself is a breeze, it has never been so easy on a different blade with J2 on it, the arc is sharp and low but you can see very well how the ball dips low after clearing the net, it is that the spin you expect is not there and a decent training partner can just keep blocking everything back with ease!
Joola GT PS was a bit better; hitting harder using some body transfer further away from the table increased the spin delivery dramatically, but previously used heavy PG9 blade worked much better with it. Also Gewo Nexus EL Pro 48, which should be softer than Joola, was so harmless unless I hit very hard, and it's just stayed harmless in terms of spin if used on backhand.
The only hard rubbers I could see performing well were Nittaku Fastarc G-1 (if it can be considered a hard rubber) and Kokutaku 007 Pro.Selected with 39 degree hard sponge. That's a very tacky topsheet attached to porous, very elastic and bouncy sponge, and the rubber feels much softer than it is.