Hi Mike,
Up through CTX 1.2, here is what you can expect:  For the TS 8710 and MSE 8510 bridge resources, the values of num screens and required capacity will be the same.  For the CTMS, the required capacity will always be one more than the number of screens because of the 30 FPS presentation data. 
In later releases, the required capacity will likely have different unit representations driven by new TS capabilities.
- John