At least with your camera 14 minutes is just too much time. You can shoot a ring around to find what ISO to shoot your Trix at. Get a short roll of TriX, 24 exposures, in open shade, a swath of white cloth, a white sweater works find, then a black swath of cloth, another black sweater. A person with Caucasian zone VI skin tones, if possible a 18% gray card. Start with ISO 25, shoot a frame, the cover the lens and shoot a repeat for 50, 100, 200, 400, 800, 1600, 3200. Then find an outdoor scene, late afternoon broad range of light vales, repeat with last 10 frame, this time shoot 100, 200, 400 and 800. Develop at manufactures recommended time. Standard stop, fix, wash and dry. Print a contact sheet using your usual time for a negative that prints well. After it dries look for the ISO that results in texture in both the black zone III, then look at the white cloth for zone VII, skin tones zone VI and and the gray card zone V. At this stage you are looking for detail in the black cloth this sets your personalized ISO, if zone VII lacks detail and are blocked, or if the skin tone is off you will need to reduce development time until you find the time that gives you white cloth with texture in zone VII. If on the other hand zone VII and the models skin tones are flat you will need to increase development time. Your final personalized ISO should give a proper retention of your out door scene.
In most cases your personal ISO will be within a stop of box speed.