The basics of arrays are dead simple
//this
something1 = 42;
//becomes
something[1] = 42;
//but enables you to do something with all 10 somethings by doing
for(byte i = 0; i < 10; i++){
something[i] = 42;
}
And with solenoids (which are slow and mechanical aka slow) I doubt it's noticeable if one solenoid is turned on 1ms later. Port manipulation does offer faster responses at the cost of you knowing exactly what you do. But like I said, controlling something mechanical like a solenoid does not need to be ns precise. 
And even with a solid state application you need some pretty specific need if 1ms or 100uS will matter that much 