I just looked up female hormone cycle over the life-time.
The fluctuations during puberty are very interesting.
It seems to indicate that PG accompanies E from the very beginning.
Based on that, I would surmise that it is not necessary to bud before introducing PG.
I am wondering if this pulsing of the hormone levels (shown in puberty section) initiates budding.
The levels peak, then drop to zero, then peak higher, then go to zero.
That makes me wonder if this is what accounts for people saying that when they re-started their regimen after a break, everything seemed to come back more quickly and intensely.
So, for someone just starting out, it could make sense to use E and PG for a week "on", then a week "off" for a couple of months (or more) until they bud and then shift to mimicking the menstrual cycle at that point.
Very, very interesting. I almost with that I could start over!