Pretty fish! One thing I do miss is that our fu no longer "stalks" its food since it's "on the stick", but it's a solid feeder and even takes mysis from the water column. You'll see what I mean when you feed the fish (headshaking, undulation of dorsal spines, and twitching of the pectoral ends). IME, ghosties work better for these fish as they're bottom huggers, and guppies typically spend their time at the surface. I do think you got yours at a perfect size and age.
Unfortunately, D. biocellatus isn't sexually dimorphic/dichromic, so there's no way to sex them. This fish is super intolerant of conspecifics, even in large setups.
Can't wait for an update and more pics.