I use the rack that came with the oven. The wire in my rack runs front to back and that is what makes this method work.
Get some threaded rod, I use 7/16 or 1/2 as I'm doing larger jigs.
Now put one jig on each wire and then take a piece of threaded rod and roll the jigs to the back of the rack.
Repeat till the rack is full.
I just bought a new oven last month. I can do well over 200 1-1.5 ounce jigs at a time. This is the oven. http://www.walmart.com/ip/16503576
It cam with two racks. If I were doing smaller jigs I'd get some smaller threaded rod and use both racks.
I've also used 1/4" x 1/2" angle aluminum and cut it to size to fit in the oven and then drilled holes in it. I used cup hooks in the holes and hung jigs and slabs from the hooks. Works great for slabs but the you can't get quite as many jigs as the above method.
The aluminum is available at most any hardware store. I used 1/4" cup hooks which I had to order. You can either cut the aluminum to fit where the racks fit in the oven or modify the rack that came with the oven to support it. I found modifying the racks to work better as every oven I've seen only has partial support on the right hand side.