Lunging Aids

Do you use lunging aids to help teach your horse a connection to the bit or to encourage them to work over their topline?  Is lunging an important part of schooling or reschooling a horse on how to work correctly?  I've been doing some lunging with Stella to work on her connection with the bit.  I'll probably quit lunging her when she's incorporated into the herd and getting turned out, but right now it's helpful to warm her up and take some of the edge off so I might as well make it productive.  

So far I've tried a pair of elastic side reins.  Did not seem effective but I need to try them again and shorten them up more.  It's hard finding appropriate sized side reins for cob sized horses.

I also tried a neck stretcher on Friday.  She seemed to respond to this pretty well, I got some good stretching moments.

I've had good results with vienna reins as well but I don't have any right now.  I like these because they aren't fixed.

I had really good results with a kavalkade lunging aid when I was working with Nikki.

Thoughts?