Actually considering it was pushing against the FPR AND you weren't running the spacer I'm amazed it lasted as long as it did. The spacer is going to keep the pressure down some anyway (just plain less tension = less pressure I assume). You may have gotten lucky with a fairly robust one that put up with it for a while, the other spares may not be so forgiving. I think I'd go back to the spacer, and the FPR since I hear the Webbers get really pissy without it.

Also, spares are never as good as new. 23100-39336, 65.52 @ 1sttoyotaparts.com, comes with new gaskets and spacer...