I think I have decided I'm putting too much thought into this project. This all started because I had a chunk of money to blow and even though the Gigapan isn't something I will use often it's something I want. Call it an early Christmas present to me.
The new tripod is an unexpected expense but there's enough left in the chunk to cover it.
Plus, based on what I know and have read here I'm not going to be happy unless I get a beefier setup to hold this rig. I weighed it today. Camera, lens and Gigapan add up to 14.5lbs.