I can't see 0.5 deg sweep having much impact on the bind effect, perhaps if you had 45 deg. My understanding of the theory is that sweep does increase castor as the car rolls into the corner because the arm is not hinging in a horizontal plane relative to the track.

On the track sweep makes the car steer more "round" in corners. I notice this mostly in on-power situations the sweep can help link together a few apexes rather than driving from apex to apex. I've also heard this described as helping "get the car into the corner".

Widening the FF vs narrowing the FR rear will depend on what you are trying to achieve. If you widen the FF block the track width increases and so does the shock angle, so you will get more skate on the way into the corner. Narrowing the FR block will keep the shock angle the same but narrow the track width and in my testing this gives more overall steering but can make the car too darty. Whichever way you do it ensure you reset check front camber and toe