
The right cage will be taller, although it might be just the same width as the single flight cage I usually recommend. So, something like 30X36X18.
I'm going to post a few cages I have experience with so you can pick somewhat knowledgeably. They're in no particular order. I have noticed that Amazon sellers are trending toward narrower cage widths -- 24 or 25" instead of the usual 30" width. please be careful and read the descriptions thoroughly. We do not recommend using cages narrower than 30" wide because Gouldians, like all finches need at least that much room to fly.
Prevue Hendryx XL Flight Cage Model F050
Prevue Hampton Divided Breeder Cage System
Prevue Hendryx Large Flight Cage Model F040
Yaheetech Flight Cage, looks like they're phasing it out.