So Ive pretty much tried most of the tips above, and Im still finding that I need to have atleast one assist on to have stability. Yaw seems easier to control and therefore have assisted tail rotor off. But there is something weird with cyclic. Its very unstable hovering. As fine as I can make my cyclic input, it either wants to fall or climb. The one thing Im not sure about is the helicopter throttle assignment. For now, Im using the mouse to set it to Fly and after that do not touch it. Not sure if this is correct.
I have practiced with Flyinside Bell47 this past few months with assistances turned down. Unless it has to do with incorrect throttle handling, I feel that if Flyinside Bell 47 is controllable while Asobo Bell 407 is not, then it points to something being not quite right with this helicopter.