Well Jimmy, as I'm sure you realised by all the n00b questions, and the title, this is my first crack at a partial mash. So things you take for granted, I'm still learning about. As always I'm grateful for anyone's insight and help, however after reading your response, which had a lot of good info, I came away from it feeling like child being admonished by an adult for not understanding how a fuel injection system works.
Perhaps a plate chiller is over kill, in the past with all my extract brews, I used close to a 5gal boil and became tired of waiting an hour to chill my wort in an iced bath tub, and a regular submersible wort chiller costs $30 bucks less than what I paid for the plate chiller, but most importantly I wanted it. I don't even understand why its important whether having one is over kill or not. Also, the recipe called for 2.5 gal to mash (more like steep if you ask me) the grains and another quart and a half to sparge them.
I don't have a large pot, I think it'd a 7 gal entry level pot, I added the valve at the suggestion of my lhbs owner. It had a bazooka screen of sorts but got clogged up by the hops pellets in the wort. So I pitched it. Folks on the AHA forums suggested leaf hops in a hops bag, I was hoping to corroborate that once more by my question. Unless a brand name bazooka screen will perform better than the generic one I had before.
Is there a formula to ensure the correct efficiency and hops exposure considering the doubling of the boil volume,? I ask because I have another kit for an Oktoberfest which I don't want to screw up.
Once again, I'm always grateful for insight and instruction.