The three things you need to do to max SA are to max the number of dice, the number of attacks, and the amount of time you spend qualifying for SA. It doesn't matter how many attacks or dice you have if you can't qualify for SA, and if you can't get a full attack when you do. There are lots of ways to qualify for SA, either by getting free movement to get into flanking, using something like Island of Blades stance to flank while adjacent, or using invisibility or other form of total concealment to qualify independent of an ally. Don't neglect any of these things in favor of the other two or your overall effectiveness will suffer.