Ya know I'm going to agree with detroit on this. If you want to be 100% sure I'd leave them in the 55g until you see them starting to pair up.
Once my female got settled into the tank with her mate I noticed that they would swim around together and slap each other with there fins to let the other know they wanted to get it on fishy style.
If you know that you have 2-3 months before they pair up I'd start with the 3 tier 55g tank stand. There's also the possibility that there first spawn might not make it so you can tack on a few more weeks to the 2-3 months. But thats IMO.
_________________
Give an Irishman lager for a month and he's a dead man. An Irishman's stomach is lined with copper, and the beer corrodes it. But whiskey polishes the copper and is the saving of him.-Mark Twain