Just a quick update, which I think has settled the decision and might assist anyone else considering similar options.
I stumbled onto this review
http://www.cloudynights.com/item.php?item_id=72
which states "
As I'd expected, on the other hand, I couldn't reach focus with any eyepiece when I screwed my f/6.3 reducer - corrector onto the rear cell."
Since I've recently acquired a focal reducer and am considering a new 2inch diagonal it appears I would certainly encounter clearance issues when using the reducer, focuser and diagonal all at the same time 
Looks like the feathertouch microfocuser is the way to go.