I've shot a lot of Rollei Infrared film behind an IR720 filter at an Exposure Index of 10. Consistent metering is possible by pointing my Sekonic L-758D spot meter only at things that look the same in visible light and near infrared.
Things like grey tree bark, dry yellow grass, rocks, bare dirt, concrete, metal surfaces, white clouds, and roadways, all seem to keep their recognisable tonalities in the NIR.
On the other hand clear sky goes toward black, still water goes dark, green vegetation goes from grey to white depending on the plant species so metering these things is too chancy for me.
Here's an example:
Sedges Lakeside #7 L.Cootharaba
Gelatin-silver photograph on Ilford Multigrade Classic photographic paper, image size 16.3cm X 16.3cm, from a Rollei Infrared film exposed at E.I. 10
in a Mamiya C220 camera fitted with the 55mm f4.5 lens set and a IR720 filter.
Meter reading was based on the bark of the near tree which kept its original tonality.