Hi all,
I come back to you after getting the responses to my original question abotu clutch cylinders, sychro problems which got a few (hard to hear) answers. Several of you think my 3rd/4th synchros must have gone somewhere into the Amazon's paradise.

I'm not at this point ready for a rebuilt of the gearbox (no tools and no know-how at hand) so I first want to make sure all the other possible problems are solved. I believed that a mismatch between slave-cylinder, clutch release bearing and clutch mechanism could lead to a sticking clutch that would not allow the box to shift smoothely.

Since I will pull the motor anyway, I'd like to make sure I have the right setup: I have several mechanisms at hand:
http://img25.exs.cx/img25/9115/PICT0084small.jpg
http://img25.exs.cx/img25/9643/PICT0083small.jpg
http://img25.exs.cx/img25/1/PICT0082small.jpg
The release bearing I recently purchased is the following:
http://img129.exs.cx/img129/254/70_1_b.jpg

I believe there is only one model of master cylinder, whereas there are two of slave cylinder. I have both of the latter in stock.
Which setup should I chose to gon onto a B20 (6 bolts flywheel)?

THanks for your help and sorry for the non clickable links: anyway to turn them into proper hyperlinks?
Cheers! Séb