As stated elsewhere, the stock phillips head screws are terrible.  Useless.  They get 'frozen' into places, and you wind up stripping them when taking them out.  To cure this, I have replaced almost every phillips head screw with allen head ones.  Unfortunately, metric allen head bolts are not readily available at most hardware stores.  If available, they usually are the 'cheapo' ones that will either rust or corrode over time.  Plus, the hardware store charges a lot for these cheap bolts.
    The answer - McMaster-Carr!   At one time you may have heard me recomment Flanders as a source for these bolts.   The bolts available at Flanders are zinc plated, and will corrode with time.   The ones from McMaster Carr, if chosen correctly, will never corrode.  In their catalog, they describe the different bolts available.  Stainless steel is the way to go.  There are 2 types of stainless steel that they sell, the 18-8 and the 316.  You can read about each, but the 316 is the choice when available.
    Yes, I have gone bolt-crazy!   The following is a partial list of the bolts I have replaced.  Not only have I replaced all the carb bolts, but the master cylinder covers, the vacuum holes in the engine, the carb rubber boots, and a lot of the 6mm hex head bolts located around the engine covers.  Ther are others, but read the list!