Sounds like you at least have success with the tomatoes, so spacing them out a bit is the easy part!
I plant eight tomato plants in one of my 16' x 6' raised beds* each year, along with companion plants like marigold, basil. Plenty of room to grow to upwards of 12' tall and quite wide once I stop pruning the suckers. I want to get back to weighing my harvest this year - I'm really interested to know exactly how many lbs of fruits each plant/type produces.
This year will be quite different though, in that I'll be starting indoors from seed. I've always ordered my tomato and pepper plants from Lazy Ox Farm (a plug for them if anyone is interested), but decided to go it on my own this year since I have a decent LED grow setup. Fingers crossed on that...
* I need to double-check those dimensions