Overall performance ratings in talent review

Content

We will be capturing overall ratings on a monthly basis then a final collaborated rating at the end of the year.  I have two questions:

1. Can we pull only the overall rating from the year end review in the box chart in talent?  How would we achieve this? 
a) Would we create two rating models and configure the talent dashboard to only pull through the rating model applied to the year end document?
b) Could we create rating model A for monthly and rating model B for year end and create two dashboards on for monthly and one for year end reviews?