Dunlop makes a 205/50-16 for the Z1...its 24.1" (close to OE diameter)
The RT615 Falkens also come in a 215/45-16...its 23.5"
The B-Stone RE01 is a 205/45-16...and is about 23.2"
The shorter tires will give better gearing. The Dunlop and the B-Stone will out-grip the Falken. The Falken is cheap, the Z1 a bit more. Pick your poison...they'll work OK.
Because the Focus, especially the SVT, likes the shorter tire for gearing, I suspect the B-Stone would be fastest.