I was thinking about getting another tortoise, but I already have a 9 month old Sulcata toroise. I want to get another breed of tortoise, but I want to make sure that they get along. There is a reptile show coming next month, so I want to make sure that I pick the best kind instead of the last minute. And I also want them to be able to live in the same pen together.

I share my opinion with many other tortoise keepers (not unanimous, unfortunately), that different species of tortoise should NOT be housed together. Any particular specie of tortoise has evolved over the years to be able to live with the particular pathogens he finds in his territory, building up an immunity to them. If you put him together with a tortoise from another continent, those pathogens could be a death sentence to the other tortoise, who has not developed an immunity to them.
Besides that, a redfoot requires a very moist humid environment, hardly ever seeing the sun on the jungle floor, while the sulcata lives in a dry desert-type of territory.
I recently took in a 70+ year old desert tortoise (Gopherus agassizii) who had lived most of his years with the same family, as an only tortoise. When those folks became too old to care for the tortoise they gave him to their son's family who had him for a couple years. They decided "Grampa" needed a friend and bought a sulcata. After a couple years the sulcata started fighting with Grampa and they were afraid he was going to get hurt, so they gave him to me. What they didn't realize was that Grampa was VERY sick! He had an extremely serious respiratory infection that in my opinion came from being housed together with the sulcata. He was sick most of the winter, but finally started getting better this spring, and seems just fine now.
Dr. Kristen Berry studies the desert tortoises and I believe she has written a paper on why the wild populations are dying. She cites one of the causes for the die-off from Upper Respiratory Distress Syndrome as being caused by exotic tortoises being released into our deserts.
You can believe it or not, but personally, I wouldn't want to take a chance.
Yvonne