Clicker training and Gentle leader/halti collars??

Hello all!
I feel strange asking this, since I have a lot of training experience, but I wonder if any of you use the Gentle Leader or Halti collars? Also, do any of you do Clicker training?

I have always done positive reinforcement with my dogs. Clicker sounds like it would be an advancement in my training routine. Having not shown dogs in obedience for 10+ years, I am out of the loop for the newest techniques. I used to train by Karen Pryor's books, and I think she came up with clicker training....?

Anyway, my dog Pebbles is a 7 year old Aussie. She's getting a bit neurotic and beginning to show separation anxiety - I believe from living with my Mom. My Mom has lived with me for about 10 years, so she was here when Pebbles was a pup. Mom is not a "good trainer" and she's going to be 80 in a couple months. What I mean by not a good trainer is that she won't enforce commands, she prefers to yell them in a louder and louder voice till the dog complies. She cannot understand how I can very quietly say "Pebbles sit" and she does.... but Mom says PEBBLES SIT...... SIT.... SIT....SIT.... &%*^&W I SAID SIT!!!!! Don't get me wrong, Mom really loves the dog, and vice versa. It's just she did a lot better with her Dobermans than she does with the sensitive herding dogs.

So, I never really trained Pebbles much. Now I am thinking that even though she is 7, she's a smart girl, and I think learning obedience would be a self esteem builder for her. I thought I would teach her only by hand signal, and then teach Mom the signals, making for a much quiter household! And a less neurotic dog! When I am speaking of teaching her, it will be far more than sit, down, come and heel - I am talking scent descrimination, jumping, etc. If I had the body for it, I would do agility with her, but I do not.

Pebbles has incredible fur- very very thick and long.... the kind of coat that collars get caught in, or matt up the fur. Hence, the thought about the Gentle Leader.

Thanks so much
Jules