Galling wouldn't happen unless the frame was heated, causing it to expand, and rub the slides ways, or dirt was introduced. If the slide was warm, it should actually get looser. All in all, about 0.002" to 0.003" clearance will do, thats a good tight sliding fit. When I say this, I mean overall fit, or 0.001" to 0.0015" per side. Since its a match pistol, I take it, you should always keep it clean, and a thin coat of oil on it. If this is the fit, there shouldn't be any noticeable play in it, especially if it's lapped ultra smooth.
You can check the fit by clamping the frame in a vise, and use a dial indicator to check for side play, and vertical play.