Create static variables in Custom UI?

I am going through the exerciese of create a custom dashboard that displays cost per VM.   I am currently hard coding inside Super Metrics the costs of the physical hosts and associated MS OS and vSphere licensing.   It would be useful to be able to assign those cost to their own static variables and then call those variables in the Super Metric.  That way I could easily modify the #s via the static variable.

I tried to create a Tag called vSphereHostCost and assign a value.   That works,  but I cannot reference the value in a Super Metric.

Any way I can do this in vCops?