Thanks Bynx,
I had been along time since I tried it. I find the more pix I take, at tiny intervals, the better the stack fill be. I'd forgotten how to do it. At first, I stupidly tried to move the camera forward, then I remembered - leave the camera on the tripod, use manul focus, snap a pic, manual focus a bit, snap a pic ... until I get to the end. I sized them all down to 800x533 and Zerene stacker did the rest.
And I see an "EDIT" button down at the bottom right, just outside the frame of the thread, see it? In fact, I used it to add this.
Hack