Drew, TMX is nomianlly a 400 speed film. A 100 speed pan film can be made into a true ortho film by using a cyan filter which should lose you 2 stops making it an ISO 25 ortho film. A tad of overdevelopment done right will give you a touch more contrast. What I am saying is that you can turn a loss into fun and in the end, into a gain. And based on other reports here, you will gain more repeatability with Ilford, Fuji or Kodak.