Sorry to be a little late - I was composing the "foreign soil" entry.
Guidelines on CP10-18:
1st printing - UL multiply by 5, UR multiply by 3
2nd printing - UR (dotted) multiply by 3
On
ebay the basic three in the original issue, (61˘/$1.05/$1.80) down from a high of $180 (ie $60 apiece) last sold for $99 (ie $33 apiece).
In the second issue a complete set of nine, down from a high of $55, is going for $30.