Well it is certainly true that there is not a magical cutoff between strength and mass for any one person. And it depends on many more factors as Kane said.
But what you may want to consider, and what people usually fail to consider when it comes to strength is how close you are working to your maximal ability on any given day.
All that pyrammiding is simply falling short of the most effective means of either goal, strength or mass. NOT that these goals in the end aren't tied together intimimately provided you eat and aren't a genetic freak who can be skinny and mega-strong at the same time (yes, they exist
).
Thirty reps is endurance no matter what your personal goal of doing it is. But it begs the question. What WERE the goals of this workout? You certainly had a lot left at the end.
Since you were using singles and doubles in there you could have gotten a much better strength workout by working up to a fairly heavy single or double and then banging out a good number of them in that range. If you can test your max for that day or if you can estimate it well that may help. It would have been much more effective to just keep working heavy instead of the pyrammiding up and down.
Then when you are finished with the strength work you do some backoffs at some median range, according to your individual tolerance, which may be somewhere between 65% to 75% or your working range for that day.
Static stretching basically puts your nervous system to sleep. It can and will reduce strength by up to 40% if not more and this effect can last 4 or more hours. Definitely a potential for injury involved and for the more technical exercises this can be a downright dongerous combo. And certainly not a way to display maximal ability and control.