You’re absolutely right marcus_civis, and I am well aware of the limitations that come with ZScript. But there’s nothing I can do about that I’m afraid. Unless Pixologic finally allows multiple plugins running at the same time (and fix that horrendous “[Sleep] not working if you’re idleing” bug).
I have a couple of “failures” of my plugin as well, sometimes paired with using image plane.
If there’s a lot of interest, I could look into building a little applicationl that communicates to ZBrush by invoking a zsc every n ticks of the timer, but I wouldn’t know how to get around to doing that. Supposedly, it could be done; as my co-worker told me once he used that technique to have 3D mouse support in ZB. Not sure how much of that was thin air though. 
I am using a combination of mem blocks and VarWrite/Reads into VarDef variables. Not the most elegant solution, but it worked for me at the time.
I’m quite busy with my iPhone game (mage-maze.com) at the moment, but I’ll have a looksie at that refresh button when I get some spare time. 