Try using the VP parameter for soft charge dissipation. I have found this parameter from the datasheet for some diodes. For example for 1N4007 Vp=30m.
For some pulse diodes, Vp has values of 60m to 90m. At least for which I have determined these parameters. You can use my file standard.dio. It is available on ltwiki.
dio.txt (426.2 KB)