@User: I expect most of these diodes to be roughly similar in simulation when reverse-biased and shouldn't make too much difference to simulation. I think the most important thing is to have the diode in the model for the diffusion resistor, because otherwise you could forward-bias the device and never know from simulation that you just inadvertently killed your circuit. As far as figuring out which diode is which and whether they are being used in the appropriate context, I think that will have to wait until after this tapeout unless somebody else wants to take that on as a side project.