It seems to me that many ppl are under the impression that the fish are gonna stay in the same tank forever. lol. I have a 55g with a JD and an oscar, they are about 3 and a half inches each, and yes they will eventually be in a bigger tank. But even if I were to explain this, ppl still seem to wanna post about how 55g is too small.
I don't know how compatible the TSN is with those 2, but I wanted to give my 2 cents about the tank size. I am sure you know that the TSN will be a lot bigger eventually, and I am sure you will put him in a bigger tank.