I am a fellow P60 owner. Got mine last August and am really enjoying it. It's a bit tight inside, requiring a very watchful eye during the bake, but it easily holds 800+ on the floor and 1000+ on the dome and will turn out great pies. I ended up renting an engine hoist with cinch straps to move and set the oven into place which made the job relatively easy.
If you ever have questions about the P60, I'd be happy to try and help.
Enjoy your new oven!