So after a bit of mucking around and finding the correct firmware and K2 improvement fork (there is 2 out there, one needs old firmware, which is the one I'm using, and one uses the beta version of the latest firmwares which I don't know where to get, but also it doesn't work with the latest release firmwares!), I've got my Carto working! 

Wow what a difference in scan speed! Literally 1 minute too get a highly detailed scan of the entire bed! I'm also using the setting where it only levels the specific part you're printing in so perfect mesh before every print and it takes seconds! 

I coupled this with a r3men3d bed and a Microswiss hotend too boot. Machine is a workhorse now, not a single failure, blockage or curled print even with ABS/ASA

Mounting for the Carto with a new shroud to fit (which uses magnets like the stock one), and a couple clips I knocked up to hold the wiring to tube (rather than zip ties), all done in ABS with the Microswiss/r3men bed/Carto

Now to try out some bigger prints. 

Note I've got my bed down to a .2-.3 deviation, but this scan was done cold, when hot it "de-taco"s it's self and sits around a .15 deviation

Finally, my Carto is functional!