Ian. In a very hard water area like yours your reading od 19/20 ish out is pretty good. Like I said if you soften your input water that will go down. Probably to single figures. As it is your RO is removing around 96% of solids which is very acceptable for a 40 inch membrane. 2 things will improve that. 1: softener and 2: more water pressure.
NWH mate. A lot of membranes are supplied dry. Not all are supplied wet like you say. E.G. Osmonic Desal and a lot of Filmtec membranes are supplied dry and these are some of the best quality ones you can buy.