@BlackZero500 I'm using a multiweapon and playing on controller, so it's the set-up that works for me. It's just two different ones, Aoe or single target. So if it's alot of mobs, aoe pallete, if its a boss, single target. However, like mentioned, you can also just opt to Zonde.
But that is what works for me, and everyone will find their niche. If what you are doing works then awesome. If I were using M&KB, I would also likely assign the extra keys on my mouse to weapon actions. It's great that they allow for that level of keymapping.
Strategically, I'm using Zonde for overall mobbing because it forks to other enemies and hits multiple enemies even if they are a bit spread out. (Charged foie has a decent range on it, but not quite as long as zonde) Also, if you have taken the Zonde-Clad skill, then every 2-3 casts of Zonde when it's hitting in a crowd, you'll become charged and can unleashed a buffed up charged gizonde(or a buffed up zonde that will fork out but personally i think running in with charged gizonde is the play here.) Typically, drop Gizonde uncharged, zonde 2-3 times, then charge gizonde for a huge overall aoe burst and repeat.
As far as mobbing goes though, as I play more and more with my multiweapon, i do sometimes just deploy the talis in aoe mode and jump into the group spamming their elemental weakness, but this puts me right into the danger for a bit more dps per pp. using zonde as above, and unleashing charged zondes for Zonde clad can be a safer option. If you're okay doing the latter with Talis, it is definitely the more potent play here.
Otherwise, generally, I only use Charged Barta against single enemies weak to ice until I have built up the first level of Barta Blot using the Rod guard/elemental bullet tech counter. Then I build up the second stage with uncharged bartas and break it on a weak point. Then repeat. Gibarta requires you to be up close no different from deployed talis and other than taking advantage of barta blot except it is a cone in front of you(which with the way the current enemies move and constantly move around you, this usually ends up being wasted effort/pp, in my opinion/experience)
And Foie enemies I just rely on charged Foie. Charged Gifoie is really awesome damage but only worth while if all three ticks will hit the boss. I feel this way because it takes 18 milliseconds longer to charge than a Foie (.22 vs .40) and does it's potency over 3 hits as opposed to 1 full power hit that I can practically charge two of in the time it takes to charge one Gifoie. If you were not gonna use Talis at all, I think Gifoie would be the next best thing for down phases. But this is definitely just my opinion/experience.
For all boss enemies, I will deploy talis in Convergence mode and rapid fire techs into the weak point during down phases and will otherwise spam the charged version of the spell they are weak to unless its zonde, in which case I spam zonde for zonde clad and charge zonde for the buffed damage, unless it's a heavy movement phase (Nex Fireballs/Gun doll's laser/flying rocks attacks). I will use Barta as listed above. I haven't really found a use for the spread shot mode, but I assume its something along the lines of trying to use GIbarta. A safer option for distant mobbing if you were gonna deploy for that way for aoeing.
Edit: Also, on my lazier days, I switch the main element on front weapon palette to match the weakness of what I was fighting and just went that route. Zonde for general mobbing/uq, Foie for Alters, Barta for Dolls. Having the said Aoe spell for that element on the back palette for increased simplicity. I would have to run 3 set-ups this way, but it was still simple enough to swap through, even in mid combat if necessary.