What EI did you shoot the Tech Pan at? If it was around an EI of 25, and you were shooting for a full tonal scale, then you need to use Technidol for best results. You can use Rodinal 1:100 or 1:150, but you may not like the results. I have also seen others using HC110 and other developers -- but unless you are prepared to do some experimenting to see what works, stick with the Technidol. If you were shooting for hi contrast, you can use Dektol. Do a google search on TechPan developers and you will undoubtedly come up with a lot of helpful information.
Mark