Well, while you're fiddling around, try Ethol TEC (follow label instructions for a starting point) and C-41 developer. Use the C-41 developer (developer only, not the entire process) for around 9'/68F giving ordinary intermittent inversion agitation of two inversions every 30 seconds, EI 16.(posted 8520 days ago)Also, you might try eliminating the sodium sulfite from the Rodinal working solution. Sodium sulfite is an accelerator, which you probably don't want.
Tech Pan is pretty contrasty stuff. I've tried a variety of developers with it; the curve shape is always basically the same, with pretty much the same CI, the primary difference being the D-Max obtained, or iow at what point highlights block up into detailless density. For TP that point is rather low.