I usually set mine up as 1.1. However, I have a 2.1 ( orange basti ) that actively breeds. I've seen the 2.1 combo and the 1.2 combo both successfully bred. THese have always been in tanks the size of a 15 gal vert or 18 gal vert. The problem with the 1.2 was one female would eat the eggs of the other, but there were still 3 morphed froglets despite that. I am assuming that the female that ate the eggs was probably the dominant ( and successful) female eating the eggs of the second. I'm sure its been done in all types of ratios, but territoriality and requisite space should be taken into account.