There is no way a 230mm clutch plate will fit in the 1.8 cover. When fitting the clutch to a standard Zetec you have around 1.5mm around the plate. If machining the fly to fit the 228mm vauxhal cover then I havnt done it so I couldn't say. But a spacer will depend on the bits your using.
Trouble is the dmf is mocked up in the engine and box at the moment.
For the track I planned on using a lightened 2.0 Fly' and clutch cover with an unsprung 240mm st plate and spaced thrust bearing. But..... I then found a billet fly' and paddle clutch so lost interest in the conversion.