Geez all I've got is cam sails. (Twin cam sails) (plus one 3.7m RAF)
Cam sails defineatly help if you sail somewhere thats gusty with holes/lulls etc because you can get going a little easier, point up wind a bit higher a coast thru the lulls better = more time planing

Plus the COE doen't move anywhere near as much as a RAF sail.
If you sail somwhere where the winds really constant then the benefit of cams over no cams isn't much.
Forget Race or Freerace Cam sails, wide mast sleeves etc they're heavy, expencive plus you really need to match the mast with them = more$$$ been there done that. Unless you compete or speed sail etc forget them!
Rigging depends on the type of cam sail you have, for a "freeride 2 cam sail" down haul 75% with the cams on the mast then put on 100% outhaul before the final down haul. Highly reccomend the Gaastra Swifts they're "light" easy to rig and big wind range.
Water starting is harder if the cams have rotated but on the flip side if they have nt the sail will push the mast above the water making it easier to "fly" the rig out for a water start.
As for the harness lines if you re under powered I think you will need the harness lines a bit forward to feel balanced but other wise for me on my smaller sails the 1/3 boom length works well and in the bigger sizes 6.8m plus 1 -2 inches further forwards seem good.
Main benefit for me is the locked in feel and better gusty/lull wind day performance
thats my 2c