The problem you have of sooty plugs is either a little bit of oil passing the rings or valve guides and burning with blue smoke, or too rich a mixture. Providing it runs OK and the exhaust is reasonably clear, run as it is for a while, it may settle down. There is plenty of information on AMAL carb tuning, so you should have no problem sorting it out. The pilot jet adjustment setting has no real effect on the idle speed on this design of carb.
Richness is indicated by black exhaust smoke, high fuel consumption, smell of unburnt fuel in the exhaust, plus other fine detail regarding performance with different air valve (choke) positions.
In an old carb, most likely cause is a worn throttle needle jet, assuming correct assembly and fuel level. Also you do not know if the carb is standard set up or has already been messed with. The air filter or lack of one affect the size of main jet required.
AMAL suggest screwing out the pilot air screw, lowering the throttle needle, fitting a smaller main jet, and a larger cutaway on the throttle slide to cure richness. Scrounging a ColourTune will help you set the idle mixture.
Swarfy.
Additional. Standard Spec. 1953 A10
AMAL Type 276ER/1DB 1 1/16" Choke at engine end.
Main Jet 170
Throttle Slide 6/4
Needle Jet .108
Needle position 2