Doug wrote that he thinks he has 3/16" rigging - that would be enormous. (Missed that on first reading). John is right, what you want is 1/8th and if you still have 3/32, it's time to upgrade.
The only other method I know for quickly tensioning a rig is a lever on the forestay - haven't used one or seen it used, but this is what it would look like: http://www.drmarine.com/proddetail.asp?prod=DS803
(I'm just not very familiar with setting up boats that don't use a mast jack - I know I've done it some other people's boats, but memory is a bit hazy on the details, so you may need input from someone with a more comparable setup).
I don't see why you couldn't use a mast jack to raise the lower portion, and with it the tabernacle a bit to add tension to the rig. But I don't see the parts listed anywhere.