Footing size for pizza oven/fireplace combo

[radninja]

I'm planning a backyard patio and looking to have a pizza oven and fireplace next to each other at some point in the future. At this point just trying to figure out what footing dimensions I would need since it would be a more work to have do it later when pizza oven/fireplace are built. I'm looking (but not set) on having a Pompeii style oven like Vesuvio 80/90 and then a fireplace next to it. Thanks!