So, now that I have these two mics here, how are you guys that do this normally positioning them in relation to each other?
Both mics in the same basic spot and blend together, or do you feel out two completely different positions for each mic by ear?
Usually I mute one and find the best spot for that and then place the other. Only thing to make sure is the capsules (not the mic itself) is the same distance from the speaker for phase reasons. Then play both together to check and correct phase issues. Phase issues usually can be fixed by nudging one of the tracks back into phase. But it's a pain in the ass and it's best just to get it right to begin with.
That said I rarely use two mics aggesively in a mix. I usually choose the one I like best and then use another to fill out a specific region by aggressively filtering out the aspects I don't like and then gradually working it in with a fader till it adds to the first microphone just right. Often I'll use a 57 just to add to the speaking range of the guitar (400-1200hz) in tandem with a very lightly eqed 421 or 409.