i'll directly answer your question: no i've never used a
super fit (it takes a pen to open and it has a single hinge
that allows the shank to swing away, right?) but.... do you
believe in the rythym (sp?) of life? the right things happening
at the right time? i believe in it more after your question!
i'm in need of superfits phone # because i need to use one and
nothing else is going to work on this ring (unless i invent
something and hand fabricate it). i've looked in all my book
directories and can't find their #. superfit is probably a
brand name that doesn't reflect the co. name that produces
them. i'll bet you have their number. could i puhleeeeze beg it
from you. 

George, M.A.B. Superfit, 1-800-765-7111. They were very helpful
when I called. They said the hinge is NOT soldered, so don’t have
to worry about that. They charge $75.00 per hour to install and
they said it takes them 1 to 1.5 hours to do it, so their average
charge was about $75.00-$100.00 plus the shank to intall. I
quoted my customer $75.00 to have us install (thats wholesale), I
am saying this because you may find it helpful in your pricing.
They will give you a 25% discount if you buy 48 shanks ( thats
more than I would need in a year), and 10% discount for a dozen.
This is going to be priced up with the finger-mate, but this
particular customer is great for selling quality so I expect to
be doing a few. Let me know how it works out for you if you do in
fact use it. Would be nice to hear your opinion. Mark P.