there is no perfect stack. Any stack could win against one person, and lose against another...
What kind of stack you make, usually depends on who you want to fight. Against a guardian, for example, you usually want to stack some missile ships in you first 3 spots (Lyth, Flysch, Chlorite). Against virals, I like g.livid(r) spam. Flysch usually works nicely against a Terran. Chlor spam also works quite nicely against a variety of people.
Just make sure that no matter what you build, whether you spam or stack, always fight with 10 stacks, even if some of those stacks only comprise of 1 ship.