I spider rig when it's slow....OK that's been all year for me because 95% of the time I only get to fish on Saturdays and the crappie know that. I've figured out the secret that crappie fasts on Saturdays.
I digress and say I really like to feel the thump on the rod handle when double dipping. That feel just keep me coming back.
As for my tip, I have times where they seem to want that thing as still as it can be. There are other times I raise the rod tip a foot or 2 and drop is slowly and they'll nail it. My wife and I both tip our 2" Yum Wooly Beavertails with crappie niblets. I like it just for an added dimension and I'm running out of Wooly Beavertails!
I normally use only two jigs separated by about a foot to 18" on loop knots. I have used up to 4 jigs to cover the water column. Hate that when I get hung up though.
Looking at buying some more expensive rods like the Huckabee series. Currently I have Wally Marshalls and B n M's. I've broken a few tips on these so looking at a little more backbone on the tips without losing the sensitivity.
We troll the jigs between 0.2 and 0.5 MPH just to change it up to help.
I'm just looking for some more tips to be successful when double dipping my jigs.