Quick update on the progress...
Initially with the saltwater pan only in the fridge my humidity was pretty bank on the range recommended by the book, but once I added the meat it went through the roof, so removed the salt water tray, this got it back down to about 80% which is ok.
Even with the humidity back down, there were no signs of it drying out, after a bit more reading I discovered if the humidity was above 80% it's recommended to circulate the air to prevent spoilage, so I dropped a little 15cm desktop fan in the fridge and pointed it away from the meat so it didn't dry it directly, and after a couple of days the external moisture on the pieces had disappeared and they finally started to darken.
After putting the fan in, I notices some nice chalky white mould appearing, according to the book, this is the good stuff. If it gets in and takes hold first, it's less likely that the bad mould, black, green, furry etc will get in and ruin your efforts.
Last night I checked in on them, to weigh the pieces and see how they were tracking (30% reduction in weight = Good to eat). When I checked them, some of the nice white mould patches had started to become a little furry.
I did some more reading about the moulds and treatment options... Apparently it's non uncommon, and easily treated, just by scraping off the suspect pieces of mould and rinsing the meat in some vinegar, so I did just that. Then lobbed them back in the fridge.
The Lonza was measuring just a shade above the target weight of 700g, so it should be good in the next week or so, the Pancetta is still a ways off, I think the thick skin slows the drying of this cut, but i'm patient.