We had a loooong thread about IR film exposure before.
I recommend to soup it in XTol 1:1 or Diafine to get a little more than 3 ASA. XTol results show less grain than Diafine results with this film.
Then it all comes down to use 6 or 12 ASA with the Efke. Meter without the filter. If your lightmeter does not allow 3, 6 or 12 ASA just set it to 100 ASA and add 4 stops (12 ASA), 5 stops (6 ASA) or 6 stops (3 ASA).
- Photograph on bright sunny days. IR photography is possible on dull days, too, but results have a tendency to be, well, dull.
- Motifs in front light might look boring, sidelight and backlighting render more interesting results.