The rest were very kindly provided by Bill Thom and Alistair Durie. Find Bill's pulp-related web site at http://members.cox.net/comingattractions/index.html
I have seen a colour variation of #5, Jan-Feb 1971. It was printed entirely in black and red against a white background and seems otherwise identical to the version shown. The arrangement of the colours, however, makes it unlikely that this was a straightforward printing error. If anyone can throw any light on this, or has seen other issues in variant colours, please contact me.