So, as far as I can tell the differences are that each number has an additional amount of exposure. So 1 has less exposure than 2 which has less exposure than 3. However they all have the same gap. The + plates and ++ plates have larger gapsThanks for the helpful tips!
I will try the Astra Green on the less aggressive baseplate first.
Are there any significant differences between the plate types, e.g. an L2 and an L2+/L3+? The OC is an open comb and should therefore feel more direct on the skin?