Just spent the last 3 hours to work around a Z-Sphere scaling issue and it seems like this is a bug in ZBrush 3.5 R3.
When you apply a ZSphere as a subtool (In this particular case i was trying to do strands of hair) you can only scale it (and it’s descendents) down to a certain point. After that hitting “E” and dragging doesn’t do anything. Also if you scale the spheres down to that point, the resulting mesh actually gives me bulges where the actual ZSpheres are. So right now the only workaround is sculpting the ZSpheres seperately and then apply the adaptive mesh as a subtool.
I did try this with 3 different models and the problems was always the same.
Has anyone an idea what the problem might be?
Another little problem (at least for me) is the virtual memory usage of R3. If i leave the program open for some time in order to search for reference images or whatever it takes up to 7 minutes until i can use zbrush again.
Never had that issue before. But normally i just quickly restart ZB and things are fine again.
Thanks in advance for your help people 
Dirk