Diaphragm springs have a lighter pedal feel than long style and multiple discs allows lower spring pressures for the same clamping force. unless the clutch is rated for way beyond your power level it should be lighter. Im doing something similar but in the stupid direction of going with smaller diameter single or double disc. 
Seth

You're OK ...

The CSC is the actual throw-out bearing. It is just activated (extends) by internal hydraulic pressure instead of a hydraulic slave cylinder and/or a mechanical clutch fork.

I was just curious to see if kit makers were making available kits for older applications.

____________________________

Sorry.  I just thought my previous explanations were clear, and merely assumed you had overlooked.
Even if the OEM fork/bearing would seem to fit the concentric unit, I would hate to have to change the clutch again should the pedal effort/etc. prove to be unmanageable.  

6 VOLTS/POS. GRD. NW INDIANA

____________________________

I had talked with ram because i needed an 18 spline clutch disc for a 10" car bolt pattern.  they have a long pressure plate that can use their 10.5" clutch. the aluminum flywheel may have different options for different pressure plates as well. if you've got a diaphragm pressure plate that fits your flywheel id run that with stock clutch linkages and release bearings. for some reason i cant follow it but KISS is the best way, especially if your not planning to own it for long and helps resale.
Seth

6 VOLTS/POS. GRD. NW INDIANA

____________________________

I likely won’t bother with it, and it will end up on eBay eventually.  I also have two spare bell housings, in order to choose the most accurate and thus achieve the least trans. wear  (though whoever inherits the car will be the only one who benefits 😁). Admittedly, I have zero experience with clutches, but assume a drop-in inexpensive/rebuilt OEM pressure plate would be simplest, and probably warranted with the alum. flywheel (100K+ miles on my current clutch). I already have a new throw-out bearing, and the discs are the right diameter/splines.
 I should have remembered that when dealing with aftermarket upgrades, there are always unforeseen complications.
 There must be a reason the concentric diaphragm units apparently all seem to need hydraulic operation (?)

6 VOLTS/POS. GRD. NW INDIANA

Daniel what do you mean by concentric clutch. looking it up im getting hydraulic release bearing or dual disc clutch. are you referring to the pressure plate with diaphragm springs? for diaphragm pressure plate mechanical linkage is fine as long as you have flat faced bearing that contacts correctly and have proper air gap. If go hydraulic make sure you have enough travel to release fully and a pedal stop to prevent overtravel. 
Seth

" ... stock clutch fork/throw-out assembly would successfully operate a concentric clutch.  I’m now having doubts, as it appears an aftermarket hydraulic rig may be required (?).  I may thus just change the discs in the OEM unit (already have  them)."

____________________________