If you tend to photograph long exposures often, consider using Fuji Acros film as it doesn't need any reciprocity corrections. Simplifies things tremendously
This is my first attempts at long exposures and that is why I went with TMAX because looking online it had great reviews for long exposures. However the UPS man will be dropping ten rolls of Acros 100 off today. I expect good things from it after reading up online. I have been shooting TRI-X for decades and know it very well but the research shows that TMAX 100 is actually faster than TRI-X 400 on long exposures because of the reciprosity performance. I think Acros will be the same I hope.