Here are the papers as I currently understand them. There are a few gaps in my current study of these...the numbering scheme is my own given that there is no published scheme that addresses the papers correctly/completely.
(01) 1E1: The first early paper with wavy lines from October 1935, which I find in use thrroughout 1936.
(02) 1E2: Mostly used in 1937/38.
(03) 1E3: Mostly used in 1939. At times easily confused with the 1E1 paper.
(04) 1E4: Mostly used in 1940.
(05) CL1A: The first clay papers from 1943. The watermark is similar to that of the 1E4 paper.
(06) CL1B: Watermark is perpendicular to the previous paper.
(07) NGR: unwatermarked grid
(08) NOP: opaque, thick, unwatermarked, and uncatalogued. Easiest to distinguish for the high values (5, 10, and 20 pesos).
(09) 2C: RA straight rays; neat
(10) 2D: RA straight rays; diffuse
(11) 2N: RA straight rays; narrow features
(12) CL2A: thin, plastic-like clay paper
(13) CL2B: thin, plastic-like clay paper, opaque and almost imposible to back scan!
The five late papers from the 1950s
(19) Official clay paper, similar to CL2A, thinner, and easy to back scan for the 50c, and slightly thick and with poor perforations for the 25c.