Technical Pan was what was once known as a type C panchromatic film, with enhanced red sensitivity. Kodak used to recommend an X1 (No. 11) yellow-green filter for correct color rendering of daylight scenes using this kind of film. The film data does not list a filter factor for the No. 11 in daylight, but 4 or 5 should be a reasonable starting point for tests. The No. 11 is somewhat hard to find these days, but a K2 (No. 8) yellow filter will give quite reasonable corrections, with reds appearing somewhat light. The filter factor for a No. 8 is 1.5 for this film. Your usual orange filter will also work, but the reds will appear even lighter. You will have to find the filter factor for the orange filter, but a factor of 2 should be a good starting point for experiments. I would bracket exposures with these uncertain filter factors.