The active half life of prop is 4.5 days. So go off of it for 4 days and start filling yourself with enanthate every 4 days. Concider it a good time to get in the 4-day habit. ;)
Take everything left and throw it away. Period.
You're far too young, not knowledgable enough and just plain in over your head. Get out while you're still healthy. That shot won't do too much.
During and after. Both while on and I supplement with Milk Thistle daily because I'm both prone to bad lower back pumps (milk thistle kills the painful back pumps completely) and I drink on the weekends.
The brand has nothing to do with it as long as you're using the same drugs in the same dosage. Whether you're wearing Nikes or Reeboks, your feet are still covered.