BEFORE you blame running issues on your carb, are you SURE the ignition components are all in good order? Always check, check and check again before faffing around with carbs/injection systems. The 'shaking' at idle you describe sounds like you could be missing a cylinder (as in non-firing). Try new HT leads, plugs, points, condenser, cap and see if that solves the problem.
Got the Weber 32/36 on my B20 - don’t know what size the jets are as it was jetted for a B20 when I bought it as a complete kit from Redline.
Go through the checklist on setting up your carb:
http://www.3fowlers.com/Weber%20Trou...ng%20Guide.pdf
Might be worth contacting Weber/Redline and asking their advice about jets. Re-jet kits are cheap and it takes a couple of minutes to change them with the carb on the car, so it’s worth having a go.
Manual chokes can be a pain on these carbs until you get them just right. Take the air cleaner off, get someone to pull the choke out inside your car, watch the activation of the choke mechanism against the throttle assembly: the choke should ‘lift’ the accelerator shaft when engaged (thus allowing the revs to rise at fast idle). You might need to put a sharper bend in the S shaped connecting rod. You can also loosen the screw which holds the choke mech onto the carb, rotate it anti clockwise, re-tighten the screw and try again.
Be aware that you DON’T need full choke on one of these cabs fitted to a B20. I’ve got mine set up so full choke means the 2 choke flaps are on ¾ closed. If you fully close them, your engine will not be happy.
Once you’ve got the hang of setting one of these carbs up you’ll be surprised how good they are.
Mike