Small thing but important, If the problem has commenced since the tuneup,check that the points havn't had the gap closed from wear of the rubbing block.Modern "professionals" don't all have the experience with point installation to know the importance of providing lubrication at this point and a nearly closed gap will exhibit this "stumbling startup" many times but usually hot as well as cold.
Excessive plug gap is a cause of hard cold start and most modern plugs are furnished with a gap more suited for electronic ignition but too wide for point type system.
Most listings would specify .035 gap for your plugs.

Bob Taylor