Ha ha ha, ah I love how thoroughly useless pretty much every longstanding member of these forums is. How dare people ask for help about a thing. What do they think this is, some sort of forum for information and assistance?
Anyway, so as not to just flame I will be somewhat helpful.
Assuming that you already have a fair handle on working with your OS and DOSBox then to start with you should download Munt from here. Additionally you'll need the MT-32 control PCM ROM which is not included in Munt, but shouldn't be terribly difficult to find. The compressed folder for Munt will have a readme in it that should walk you through installing it.
Finally, to use Munt through DOSBox you need to know what number to put after "midiconfig=" in your options. To find out, start up DOSBox and enter "mixer /listmidi" which will have dosbox list the midi devices it detects on your computer, simply put the number associated with the MT-32 emulator after "midiconfig=" and you should get a passable emulation of MT-32 sound (obviously if you were to get a real MT-32 off eBay it would be better but that is often not an option).
As for which games sound best using which device. I'd honestly say you should experiment. The same settings can end up sounding radically different between games, and sometimes the card a game was designed to use just doesn't sound as good as another card which was coincidentally made better use of by the game.
The sound entry on the wiki can be helpful in figuring out what the different devices have to offer.