Do the arithmetic before you do anything else. A roving magician works a small cluster for a few minutes, gets them loud enough that the next group turns around, then moves. Multiply that out and one hour covers a modest number of clusters, not a room of two hundred people, which is the calculation almost nobody runs before enquiring.
Melbourne makes it worse in one specific way. Laneway bars, warehouse spaces and multi-level venues split a crowd across rooms and stairwells, and a performer cannot rove through a floor they cannot reach. Tell each magician how your space is laid out, not just how many guests you have.
Top picks are the acts in this category in Melbourne, without a review, rating or premium ranking: all these sort keys are tied.
This category sells in blocks, usually one, two or three hours, which makes quotes easy to line up once you have decided how long you want. Adding a second hour normally costs less than the first one did, since the drive and the getting-ready are already in the price. Distance is what pushes it up, so a Yarra Valley or Mornington Peninsula event sits above a city one.
Ask each performer directly and expect a range rather than a number, because the honest answer depends on how tightly your guests are grouped. For a big crowd you either buy a longer block or put a second magician on the other half of the floor. Anybody who promises to reach your entire guest list in sixty minutes is selling rather than planning.
Almost nothing, which is the appeal. No stage, no power, no sound, no get-in time, and they can start a minute after walking through the door. The two real requirements are enough light to see hands properly and somewhere to leave a jacket, so a courtyard event that runs past sunset needs the lighting plan checked with the performer.
It suits the awkward hour better than anything else you can book. Arrivals and canapes at a Melbourne work function is a room of people who half know each other holding drinks, and a magician gives them something to react to together. Save any stage-based act for later, once people have settled and have somewhere to look.
The first fifteen minutes of a Melbourne function is a thin room of early arrivals standing near the bar. A magician working that window warms the place up before the main crowd gets there, and it costs nothing extra.
Floor staff who have not been told there is a magician will walk through a routine or try to move them on. One sentence at the pre-service briefing sorts it out for the whole night.
Working a standing crowd and working people looking up from a chair between courses are two different sets. If you want both, say so, because not every performer has rebuilt their material for the seated version.