1. No
2. Personal preference. There's no advantage to a finger whistle.
3. Nope.

Finger Whistle
 

My first year I used a neck lanyard whistle. There were many occasions where I was "looking" for my whistle at the end of the play. Also had a few instances of the whistle bouncing around and distracting me.

One of the veterans in the association suggested I use the finger whistle and I was skeptical because it was just foreign to me. I have been using it ever since. I will not go back to the lanyard whistle under any circumstances.

I agree with the other posters that one-handed signals look ridiculous, but I have never given one. Simply blow the whistle first, and then give the proper signals. I have worked all positions except U, and have used it w/o problem.

I generally wear a wrist lanyard only. I spend most of my time working as a U. On the occasions that I have worked as HL or LJ I've worn a neck lanyard also.

1. I use a finger at R and U, and a lanyard at the other positions.

2. I talk more during the play as R and U and so do not want a whistle in my mouth. A lanyard tends to bounce around and I would have trouble finding it compared to a finger grip. In other positions, lanyard is fine since I worked many years of basketball. My last IW was using a finger grip anyway.

3. Same for HS or college.

I use a whistle at all positions. When I'm a wing, I use a lanyard whistle as well. Before the play starts I keep the lanyard whistle in my mouth in case of a dead ball foul. At the snap, I spit it out and use the finger whistle to kill the play.

I feel the finger whistle gives me more control and agility. While I don't like to see refs giving "half signals", I don't think this is hard to do. I simply don't signal until I've blown the whistle, and have enough time. I'm in no hurry to signal a TD or anything, one extra second won't hurt anything.