Well if you are HuyMac, the best strategy is to get 6-10 skirantras regardless...
If however you actually want to be good, it is generally best to only get one cap as TEC or Advent before rushing titan...sometimes, it is useful to get a 2nd cap if you really need the planet bombing and support for wiping a suicide player, but generally you are better just building more LFs and corvettes...
I will say that smaller maps tend to lend more to building a 2nd or 3rd cap before getting a titan...
As Vasari you may want to get 2-4 titans before getting your titan....rebels can use SBs for their firepower (caps are for support and SC), and loyalists need caps for planet bombing and stripping (and possibly labs)...