I've used those compounds.. and together..
You don't need Deca in that stack, especially if you aren't familiar with how you react to what you already have designed.
Piston, Nandrolone Phenylprop is Nandrolone .....and Nandrolone is Nandrolone, be it Decanoate or PhenylPropionate
The gains are slow and steady with it.. a lot of people get very bloated with it's use... LBM gains are LBM gains, but I would run any NPP cycle longer than 4 weeks in my opinion... If it was straight Test Prop and NPP, I would go 8 weeks.
I do see some logic to running the Prop Preps 1-6 as Enan takes that long for me to rear it's pretty head... for me at least. I would only use Test Prop at the beginning and save the Drost Prop for the tail end if I was bookending the cycle with the Props though.
**optional 1-6 Test Prop***
Dbol 1-4
Test Enanthate 1-12
Drost Enanthate 1-12
Test Prop 12-15
Mast Prop 12-15
post cycle therapy 16-18,19