I'd say a 1.1 in a 10 gal would be fine.I have my Costa Ricans in a 20 high and have a 1.3 in there now.Some people on here say their auratus are shy but mine are as bold as my bicolors are.I even reached in the remove the feeding dish and had to move one outof the way and it turned to see what I was doing after it jumped about a whole 2" so I could remove the lid.
I think the Costa Rican morph is one of the boldest,IMO.
A 10 gallon would probably work for a 1.1 pair of auratus. But if you have any bigger tanks, I would suggest them. I have my breeding azureus in a 20 gallon long, and they still seem a little cramped for space. I know it is a hard comparison, since azureus are bigger frogs, and I have a lot of plant cover in my 20 gallon long. So basically, your 10 gallon will work, but I would suggest a bigger tank if possible.