Outer Limits 4x4 Board

for flex what would be the best shackle angle to have sittin level ???

atm in me 47 cruiser sittin flat me shackles are pritty much straight up and down . am i right in assuming that if i moved the shackles so they angle more to the rear (either by movin the chasis/shackle mount in or longer springs) sittin still that i would be increasin the amount of flex i get???

yes you are right

You will also get a smoother ride with a bit more of a shackle angle.
You will only get more travel if your springs are flexi enough though.
If they are rock hard you will only get a slight increase in travel moving your hanger.