Thanks so much for the thoughtful and thorough response Michael!
It is a unique experience to be able to communicate with a developer directly.
The rebuild command is what did the trick here!
In the end though I discovered the best solution was a profile and 2 rails.
Simplicity seems to be the key to most problems.
I am thrilled with the result.
I will continue to explore Moi with excitement and spread the word!
Starting with my Rhino frustrated jewellery making wife:)

Mostly though I would like to say that your efforts here are so greatly appreciated!
Moi is rare gem of intelligent design and functionality distilled down to it's essence.
A pleasure to work with and an inspiring creative tool.
I look forward to seeing what V3 brings!

Cheers
Stavros

Heres a screen grab of the final product
Simple but elegant