On occasion, I have used mine with a chain to pull a stuck mower out of the mud. There was no problem with that and the TT has plenty of power to do that. However, I have no experience with long term "towing" such as you are planning.
Keeping in mind that inexperience, I would say that if you are in the flat part of Texas and you are truly mowing well kept grass(versus "bushhogging") then you might be OK with that.
Two major concerns would be 1) the weight of the finish mower and 2) how are you going to attach it? It would have to be offset to the right or left and that would probably stress the pumps to keep the mower tracking straight, but I don't know how bad.
That Scag is going to cover the ground pretty fast. It would be hard to imagine making better time towing the other mower even though you are making a twice as wide cut.
Maybe someone else on here has experience with what you are proposing.
I also did a lot of research before I bought and concluded that the TT was the best of the best. I have not been disappointed. Yours will do a great job, too.