Nice, yah i spent sometime reading and re-reading the Default.ReaperOSC and eventually got it doing everything i wanted!
If anyone is wondering the same thing but intimidated by the config files.
It really wasn't that hard at all.
Just take a look at "Default.ReaperOSC" and look at some other config files people like fundorin said. The syntax for .ReaperOSC files is super simple once you give it a close read.
For anyone interested the key parameters to do multiple faders and banking are:
DEVICE_TRACK_COUNT 8 (or how many tracks you want to control)
TRACK_VOLUME n/yourMultiFader/@ (use something with a wildcard ( @ ) to map to a select number of faders )
DEVICE_PREV_TRACK_BANK t/NameOfYourTogglePrev
DEVICE_NEXT_TRACK_BANK t/NameOfYourToggleNext
I use TouchOSC and I figured out a lot by mucking about with this great config that someone made based on the TouchLogic one:
https://www.youtube.com/watch?v=Z2QoJzDWVuw
Another useful thing is you can use the " Listen " button in Reapers control surface settings to see the exact message your OSC layout is sending to reaper. Sometimes in TouchOSC an extra digit was being added into the control message for some reason, so I needed to need that into the config file.