I need some advice about dining tables, dining room setup, etc.

First, I'll tell you what I have. We have a high-ceilinged, gothic-revival style Victorian house. The dining room in particular is unusual because it has SEVEN doorways with every wall having at least one, and we use them all several times a day. Its size is about 15 x 15 with a small alcove where I put my china cabinet.

Well here:

The chandelier is staying as are the checkerboard tile floors and it's already been painted a very gray-violet color. There's 36-inch tall white wainscoting too. What I really need help with is dining table.

I love the round table, and the one we have currently is 54 inches. Comfortably, it seats 6, but we will crowd 8-10 with smaller chairs most Sunday nights.

Which brings me to Sunday nights. It's our family/friends dinner night and we normally will have 10-12 people and this setup just isn't working for us. Our numbers can go up too. At 14, we had to totally take out this table and set up 2 banquet-sized folding tables side-by-side.

Anyway, what I really need is a table that will seat 10-12 not necessarily comfortably, but adequately. LOL I'd love to keep a round table, but have no idea as to what size I would need. I think that maybe an 84-inch round would be adequate and with smaller chairs and I THINK I would have adequate clearance around. I just don't know....

What do y'all think? Is there some kind of formula? Should I dump the idea of a round? GAH. This is hard! LOL