The higher the "angular drag" value, the quicker the rotation will stop. It will also make it require more force to rotate, so you will probably need to raise the roll/pitch rates too.
That's correct, the expo setting in the sim is either on or off, so the only way to tune it perfectly to your liking is to use a radio where you can adjust it.
Glad to hear you liek it and that it has been of good use to you!