recalibrating the FMU

I have a vortech FMU and want to recalibrate it. I have the new calibration disk but do not have the diaphram. Can I re-use the old one or should I try and get a new one? Where would I be able to find one of these (besides Vortech).

Also, how do I tell what size calibration ring is for which injector size? I think the one I have is for 24lbers.

Yes, u can reuse the rubber seal if that is what u r referring 2...Inj disc sizes r as foll: 19#/12:1= 2.72"...24#/8:1=2.22"(Cobra's 10:1=2.47")...30&36#/6:1=1.85" & 38-42's/4:1=1.59"..that should b enough,i hope....