Thought I'd get on and summarize the end result with a few points I learned along the way.
1. Using PB2 in the boil & secondary provided very little PB flavor to my big porter (7% ABV)
2. 8 oz. of Lactose in a 5gallon batch really helps sweeten the final product but will lead to a confusing FG reading of you just rely on BeerSmith's OG values.
3. PB flavor is best achieved using the liquid extract (2 oz Watkins added to a tertiary vessel but will just go into secondary next time)
Overall results were great and well received as a sweeter Chocolate PB porter.
Hope this helps with the learning curve for others tackling a PB beer.