tpfan control settings? which are ideal, just the default tpfancontrol smart (tpfancontrol.ini)? or manual?

I did a post earlier about my loud thinkpad t430. I opened it up and there was not that much dust in the fan itself. I downloaded tpfan control. I'm currently running it on the bios setting. But should I do manual or the smart setting? The program say my temp is around 60 and usually below that. When I set it to the smart setting the fan is 0, (the temp is below 50 degrees which I think the default settings of tpfancontrol turns it to 1 when temp reaches 60). What are the ideal settings for computer health and also not an annoying loud laptop. I don't mind the sound itself. I just don't want to bother people at college when I'm in a classroom or library.i'm comparing sound levels of each manual setting and i would say before I had the program, the laptop was always at a 3 setting.