Tren with decca is a no no.
If say run Tren/test/mast for 10wks. That's a blast of short esters.
I'm pretty sure you could run that dose for at least a year without any issues IMO. I personally know someone who hasn't come off of 700-1000mg tren for over a year and he's doing fine. I have run 700mg tren for 20 weeks with my blood work bouncing back within a month, IME.