When you guys use this bait, how heavy of a weight do you use and on a spinning rod or casting?

It all depends how deep you want to fish! Deep water I fish 1/2 and in skinny water 1/8 .You can fish it on spinning or casting.  I use a Norman's speed clip as the lower split ring,this way I can change my weights fast and easy.

I make my own.  I fish them for the most part on bait casting tackle.  One of the primary points of the rig is to get to the bottom asap, so 3/8 is about as light as I make mine up to around 1/2 oz give or take a couple of grams.  I have made some heavier jika rigs, 3/4 and up to a full ounce but I haven 't given them a fair test yet.  Last year my best size were rigs that were right around 1/2 ounce