I already have two tube amps in mind, one built with more of an American voice, and the other British. My main axe is an Epiphone Elitist Casino, which is FULLY hollow, for some who like to argue… Anyways, I want a nice warm, and crystal clear clean sound, so which would be my best bet in terms of achieving the "ultimate" clean sound?

American voiced amps tend to use 6L6 or 6v6 power tubes, and typically have strong bass response, slightly scooped EQ tendencies and plenty of headroom. British voiced amps commonly use EL34s/EL84s and are characterized by quick breakup, an overall looser sound and lots of mid range. I’ve always preferred Fender style cleans, which are definitely American voiced amps, but there are plenty of good EL34 powered amps that can produce great cleans. Above all, you really need to play both amps before you buy one, and see which one you like most.