Basically here's the deal- I want to record voices for my own characters, but I don't want them to say generic things like "good day" when out of dialogue, because it clashes with the voice I've recorded for them. Any advice?

I would make a quest that has a priority of 100 make all of the dialogue linked to that quest. Make all the necessary voice options for said character and make the getisid as the actor of your choice. The stuff you want to change is in Dialogue>Conversation>Hello,Goodbye also Dialogue>Topics>GREETING. There are others options that are in the services tab for the dialogue tab for example the barter stuff for vender. You can also technically make it not say any of the lines through a surefire way, as in use the getisid tag in all of the conditions for the dialogue for your specific race. This may result in what is considered a dirty mod.

I'll give it a shot. Thanks!