Personally, I would strongly suggest you double, or triple-check the two lug patterns. There is more than one instance of a metric and SAE pattern being close enough to bolt on, but they still aren't right, and to use a metric pattern on an SAE hub is a hazardous, or even dangerous practice.
The "donut" spares do have a good rim on them, it's the tire that is not rated for long-term, or high speed use. Once you wear that "donut" tire out, it's not a problem to have a regular tire mounted up, and continue using the rim.
Roger