Both these people have given you good advice so far. You would think that you would get twice as many everything with 2 plants per pot, but it just doesn't happen. One plant will always lose out and be smaller when they fight for light, root room and nutrients. If you want thickness, then you can always trim back the branches, ot tip the plant, to make them bush out while they are growing and haven't set flowers. I have noticed that once they start to flower for the first time, they also branch profusely all by themselves, so early branching will delay your first set of peppers by a little bit, but you will have more branches which usually means more peppers. Some of the people on the forum are complaining about not enough peppers on their plants, but from what I see, just about every new branch seems to produce at least 3 flowers from each node, at least on all the plants I have tried so far, which is only 6 kinds so far. I know my red savina plants I grew a couple of years ago did the best for wanting to branch by topping them off. One plant had 18 main branches on it when it was still 20 inches tall.
I grow all my plants in 7 gallon containers for the first 3 years, so I am doing pretty much the same as you want to do. I do however, start them in small peat pots and once I have good established plants, I put them in larger pots and the roots can grow right through the peat pot. They work great. It ia also suggested that you might want to pot them in something small until next spring. That is a very good idea. If you are going to grow these inside with lights, then that does not matter. You didn't say, you may want to just store your seeds and know that you have them to start next spring. Store them correctly and the seeds will be perfectly fine for years, yet alone a half of a year.
