Ans 1> I thought it might be possible to combine Join & Rebuild in a single left-click action - that is, after I've made my selection.
Is it actually possible to have a button respond differently to a right and left click?!(That would be very useful for minimizing button clutter).

Yes I planned to add all my custom buttons there("bottom toolbar").

Ans 2> re:bottom toolbar

Ans 3> Exactly right. While point editing, I often find myself unpleasantly surprised by, what at first seem continues stretches of a curve, spikes:


Ans 4&5> Thanks, that fact will save me the effort. I would still find it useful to pu the "Plane" button in said toolbar - left click = activate right click = reset(assuming this is possible).

Thanks,

Kiril

Edit: Just realized the Cplane button already resets the plane on right click! - that answers that.