extra yeast ?

[owbeeon]

hi, just started messing around with some kits,
ive read several posts concerning adding extra sugar ar to increase the osg,
will the original amount of yeast cope with a certain amont of sugar or should extra yeast be added in equal proportions,
also does incresing the osg ultimately leave you with a higher fsg, if so is there a rough allowance for that,

conditioning : morgans golden saaz
claxtons dark real ale