MZ/MuZ Riders

Can anyone help..I'm looking to use a mikuni carb to replace a worn out polish carb on my es250/2. I know that some people have used 30mm mikuni carbs on their 250 mz's....but none of them are 250 trophy's. Does anyone know whether I should use a 28mm or 30mm carb....and what jets to use..I am clueless,=,.
anyone out there?
ps HAPPY NEW YEAR TO ALL !!!!

Can you measure the inside diameter of your intake manifold with a vernier caliper? I'm assuming this diameter has some relation to the size of carb you should choose. Always a good Idea to ask about this on the MZ_RIDERS yahoo group as well (http://groups.yahoo.com/group/mz_riders/)

David.