Chocolate peanutbutter porter advice

This is my first post and I'm on my 9th homebrew batch. I made a brown porter (flag porter clone) and this will be my third time making it. In short I want to take about a gallon out of my current batch, before I rack it off, and experiment a little. I'd love to make a chocolate peanutbutter porter, but there is A LOT of different opinions out there. I already have PB2 powdered peanutbutter and I'm just trying to figure out if this is something I can do in a 1 gallon Carboy or will I need to add the powder at flame out of my next batch? Same question applies to chocolate as well. Have I already missed my window to add these flavors?

I added mine with 5 mins left in the boil. It turned out awesome

I know you can age on cacao nibs in your primary or secondary, but the powdered peanut butter extract does best in the boil near flameout.

I did pb2 at 5 minutes and in secondary turned out awesome!

I've been looking for the powdered peanut butter. Where did you get it?

Amazon is where I found the best prices for it.