George, I just appreciate you following along. I have a couple other topics I have been following, but haven't had time to look at in the last couple days. My Inbox is loaded with updates from them that I haven't even looked at yet. 
I understand what you mean about the helix and lower level staging yard. I do value your advice, because it is from experience. It is a big concern whether it will be a literal pain in the neck, back, etc if I am even able to build it.
Another concern that my wife brought up just since I wrote my last replay. She asked if we had to move to a single level home, whether I would build something that is too hard to take down and move. The possibility is very real since we both have knee problems. We have been told we need knee replacements but won't be able to get them until we retire. (I am wondering if that means insurance won't pay and wants to push it off to Medicare.) My knee isn't that bad yet, so I can envision a 4 year wait, but my wife's is far worse, and she is 3 1/2 years younger than me.
So, I have to keep in mind that whatever I build has to be built in such a way that it can be dismantled in sections to hopefully reuse. The helix and lower level make that more complicated for sure. I can envision taking the sceniced top off the helix and having the helix a separate unit, but two independent levels make it more complex to design, build, and take down.
You are so right that we aren't getting any younger, and it may be that the whole idea of a staging yard would be impractical. Cassettes are certainly easy to move to another house! 
Thank you for your input!!
