First of all, I'm confused on what is a Unique Variant. I crafted my Glacius not too long ago and got 3 UVs. They were low against beast and gremlin and med. Against undead. Is this something I should worry about or be happy about? Anyway, I'm also going to get both a Supernova and a Polaris. Should I get one or is both good? (My only other gun is a Valiance.) Please respond, and feel free to friend me. My IGN is Flarey.
Glacius UVs and Pulsar Desicion
Since the Glacius is elemental, the med undead is good, but since beasts and gremlins are strong versus gremlins, those are useless. Just treat it like it has an undead bonus only--that is actually good for FSC.
As for supernova and polaris, you should probably go for one or the other. There are other threads in the Arsenal about the choice between supernova and polaris, but unless you are mainly a gunner, you don't want both since they have very similar uses. If you are mainly a swordie, most of those go with polaris since it's good for a lot of things that are hard to kill with swords since a lot of those are weak versus elemental weapons.
Read the wiki page "Unique variant" to learn about unique variants. Yes, they are good for you, although stronger UVs would be even better for you.
Usually, an elemental gun is preferable to a normal gun, because turrets are disproportionately weak to elemental damage, and guns are great against turrets. I'm worried that you'll end up with an all-elemental loadout, and hence be weak against beasts and gremlins. Read the wiki page "Damage", to learn the monster vulnerabilities and resistances. You may also find my sword guide helpful. (It addresses mixtures of swords and guns, as well as pure swords.)
It's meant to say med against undead and low for both gremlin and beast.