Welcome docchiro!
I was in your boat many years ago, 3 adults and 2 kids. I started with a 22, which usually worked out OK if I planned the cook and didn't go crazy with the sides and apps. Some cooks were pretty much impossible due to timing issues. I solved the problem with the addition of another 22. This worked out great, as I could have different heating configurations for each. I typically used one grill for the main course, and the 2nd grill for apps and sides.
There were a few times where a 3rd grill would have been very helpful, especially while entertaining.
I eventually upgraded to a 26, and it has been a game changer for me. The additional space is significant! I can do large cooks for 10 people without issues. If things get complicated or I want to show off, I can fire up my 2nd 26 or one of my 22s.
My advice, start with the 26. It will solve most of your problems. They're difficult to find used, so I would just buy new. It's a pricey grill, but worth EVERY penny. The grates are heavy duty, $90 new. Many stores don't carry the 26. Amazon has free shipping on it
HERE (even if you don't have amazon prime. Although with prime you get free 2 day shipping.
free amazon prime trial here.
For your 2nd grill, and to really set you up for smoking and bbq, I would pick up a Performer. No need to go new, watch your local craigslist for used. In many cities, you can pick up performers for 50 - 150. The ones under 100 usually go fast though. PRO TIP: Search for weber|webber|'charcoal grill'
I recommend the performer because its really fast to fire up and the work surface is incredibly beneficial (especially while cooking with multiple grills)
Once you have your performer, hit up cajunbandit.com and get yourself the BBQ Stacker. You'll be able to smoke ribs, briskets, butts, chickens, you name it. It kicks the ass off any other product or method out there. (other methods for smoking on your kettle are covered
HERE