First i think that Gin fizz has less lemon juice than tom collins , then Tom
collins is served in a collins glass while gin fizz is served in a highball
glass , i also think that gin fizz can not be given with full ice ....it's a
bit like the mudslide and the screaming orgasm i mean they are both made out
of vodka , baileys and kahlua but the dosage is different ....do not forget
the garnish , it also differs ......
As for the b52 , as we all know that cointreau and grand marnier are both
orange flavoured but there are some differences among them ; the grand marnier
contains vanilla and cognac in it , cointreau don't ... u can not be so sure
about the b52 , but i think it differs from place to place , i mean where i
used to work , they used to use cointreau , now it's grand marnier , u just
have to abide by the rules of the club ; to be honnest i think that grand
marnier goes better with tia maria and baileys cuz of the vanilla in it , but
as i mentioned b4 u just abide by the rules of the club ....
well i tried my best , hope this had helped .....