I am a bassit who plays electric upright and regular fretted. All of the presets i see here are made for guitars to imitate bass. In general, the software is the best out there (i tried everything) but its all clearly designed for regular guitarists. Whatever you get out depends on what you put in. How awesome it would be if we had a ToneLibGfx Bass standalone instead of half baked ToneLibGfx Metal release? Or even better - presets for bass that assume your clean raw input IS a bass?
There are some out there, the double bass sim is particularly interesting with a fretless will post more if you want something in particular will give it a try.