I also have an engine built by Joe Lapine with a Canton 8 qt pan, and cooler. My total when everything is dry is just a shade over 9 qt. I had to re-mark my dipstick as well since full is just under the "O" in Overfill marked on the dip stick.
I'd recommend that after the
oil is drained you just put 8 qt in, give it a chance to drain down and remark your dipstick at that point.
DonC