Total Ascent overlay?

How can I get a total ascent overlay? This is not an elevation overlay where the numbers go up and down with altitude, but the total feet climbed so numbers would only increase.

I am comfortable editing gauges and gpx files, so could happily customize a gauge intended for another purpose if need be. But, if there is a way to do it using the elevation data in the GPX file, that would be preferable.

So,
1 - is there a field in GPX files for total ascent?
2 - if not, is there a way to get Virb Edit to use the Elevation field data for such a gauge?
3 - if not, is there a better solution than overriding HeartRate or Cadence to hold the total ascent data at each point and to customize a HR or Cadence gauge?

Thanks.