Aside from the great gains you can get with Testt; Primmo will still shut down your natural testt production. Maybe not as much as Decca, but still some shut down will occur. So some testt is needed to counter balance this.
If you believe your gynoo sensitive then perhaps Testt-P is a better choice for you, as you can bail on the program faster than with Testt-E.
I'm 45 and have never had gynoo issues, so I don't think advancing age is a primary indicator of who'll get it.
If lean mass and striations is your primary objective you can't go wrong with Trenn, but again Testt will be needed to balance out your depleted natural production.
I'll repeat that I have never used Primoo, as it costs twice as much as Decca, with half the growth potential - or so I've read.
I have used Testt-E and Propp, and I consider Propp to be near useless compared to Testt-E (Don't hate propp fans, that's just my personal experience). Mg to mg Testt-E will always be a better deal.