okay give me some patience as I am still finding my feet here, don't know how to place multiple quotes on one reply,
anything I tag/term experimental has been discussed and agreed upon by all of the team before starting to come up with any better idea first,
Old monkey - choose a single line as there was no knots or joins so less weak points for failure given the load force that was going to be generated,
Southsoundtree - yeh the load application was less than desirable - I agree ,
ClimberNz - cheers from across the ditch

setup was pushing it x9000, single 19mm bull rigger line running down the back of two trees at best position we could use, down the backs for max load sharing to a porty set around base off each tree with whoopie 's so two base ties one length of rope. used a pulley /sling combo to allow the stretch of the rope and movement of the two trees to absorb the shock load.
then the pulley was to let the load find its own centre, tag line on the tip was for directional pull away from other trees on the back cut and then for directional control away from same trees if needed.
Page - the structure of the tree including the second defect (the one at the butt in front of me) meant it was unsafe to continue climbing past that point and the rigging point strength in the two trees being used was best for height vrs strength at that critical junction so we went with it there.
phew thats a lot of explaining so hope it all comes together - keep it simple stupid and hope like hell would be the motto on this one - the whoopie is going in the retirement bin and thats a rap crikey.