Three different dies were used. They differ in the strength of the lines in the clouds. The second die was used in a special booklet plate.
Die 1
Die 3
Die 2
The initial issue on 1 May 1935 was on paper with a single watermark. The stamps were perforated 14x13½ and they were from die 1 in which the lines of the clouds are not well defined.
The two plates had 480 impressions in two panes of 240 and
the issued sheets had 240 stamps in 10 rows of 24.
The first plate had pane numbers A1 and B1 and the second
plate had pane numbers A2 and B2.
The number is under the second stamp in the bottom row.
Later in 1935, there was a small issue perf 13½x14 from pane B2. These stamps have line perf characteristics as seen in the example on the left.
A special plate was produced to make booklets and the stamps were issued in November 1935. The stamps are from die 2 and the lines in the clouds are much stronger. Due to the layout of the plate, one third of these stamps have an inverted watermark.
The booklet panes had advertisements in the margins.
In April 1936, stamps were issued on multiple watermarked paper from a third plate with pane numbers A3 and B3 and in August from a fourth plate with pane numbers A4 and B4. A third die was used with these plates. The strength of the lines in the clouds is intermediate between dies 1 and 2.
New booklets were issued in November 1936 with the impressions from die 3.
The 1d was replaced by the George VI definitive in 1938.
The above information is taken from The Postage Stamps of New Zealand Vol 1, 2 and 4 published by the Royal Philatelic Society of New Zealand in 1938, 1950 and 1964. All scans were made by the author.