I'd suggest the irish moss which goes into the boil. Isinglass goes into secondary.
But, who really cares whether an oatmeal stout is crystal clear?

Agree - skip the isinglass. Unless someone's putting this in a sightglass I don't think it will matter.

I'd adjust the fining agent down from what was used on the original batch, though. Unless you want gelatin stout on the garage floor, in which case, rock out with your cock out.

Another question, how many volumes of CO2 should I carbonate this beer to?

in the BJCP guidelines, Oatmeal stout has moutfeel which says: "medium to medium high" carbonation.
American Stout says "medium high to high carbonation".

I'd go for the neighborhood of about 2.75 to 3 volumes on it, leaning closer to the 3 than the 2.75.

my .02

HTH-

brewed this 2 weeks ago...can't wait to get it kegged...brought it up out of the basement for a couple of days of a little warmer fermentation, then back to the chest freezer to crash then keg...all gravity readings have tasted great! i know i only need a drop or two for my refractometer but while i'm in there.....

Steelers&Beer: How did your Shakespeare stout turn out? Mine is absolutely delicious! I could drink this all the time! I couldn't find pacman yeast so I used wyeast american ale 2, I think it is very similar to the clone except my head color was darker was this the same for you?

the shakespeare stout clone turned out fan-friggin-tastic! i took a growler on the brewbus yesterday and shared it with about a dozen guys, great reports all the way around! Love the stuff, going to brew it again soon! Great job fellas and a fantastic recipe!

WOW, I brewed this beer with the smaller amount of r.barley ... it was perfect.
I always said this was my favorite stout. It has a perfect dryness to it. JP said it right THIS STUFF IS GOLD !