Watermark: Multiple Crown CA (sideways)   -   ½d & 1d were issued on thinner paper and with brownish gum in 1913.
Most images: "Tikopia" collection, the thin paper stamps from the original Tulagi.com site.
 

Watermark (reverse)
Multiple Crown CA

green
1 Nov. 1908

green - Thinner paper
March 1913

red
1 Nov. 1908

red - Thinner paper
March 1913

greyish slate
1 Nov. 1908

ultramarine
1 Nov. 1908

red/yellow
6 March 1911

olive
1 Nov. 1908

claret
1 Nov. 1908

black/green
1 Nov. 1908

purple/blue
7 March 1910

red/blue
7 March 1910

green/yellow
7 March 1910

SPECIMEN stamps of this issue (images thanks to "Tikopia" collection)