I wondering how I can only show Percentage Complete?
You can go with the simple solution here. You can select only one measure you would like to see on gauge report and remove any other.
In many cases, this is suggested a way how you would like to build a gauge report. You can use only one measure (or two measures if you want to use one of them as a gauge limit for another) for gauge chart.
You can create several gauge report (containing one metric in each) and then combine them in Dashboards.
In this Chart type dashboard in our demo account, we went with this approach. We are using only one metric per one Gauge and then put them side by side in the dashboard.
Daina / firstname.lastname@example.org