PoE Doryani's Prototype, Templar, Chaining builds

Hi there! So I'm working on some new builds, and I have two questions about how PoB handles certain calculations. 1.) The first question is very simple and has to do with Flame Blast. When you see the 'cast rate' while having flame blast selected I assume what that is trying to represent is stagers per second, right? In other words, if we assume an unmodded 10 stage max flame blast, and my cast rate on the PoB is say 4.5. That's telling me that I'm casting 4.5 stages a second, so my time to do the 'average hit' damage on top will roughly be 2.22 seconds? So I'd have to divide that

So i think i have finished my pob of the shock slinger. Gotta replace the 6 link arc with lightning conduit and add overcharge support to the 3 link arc but thats about it. i tried to be reasonable with the items since its a league starter but who knows what the actual prices of these will be. Guessing ashes of the stars might be a bit much like this league but we probably have other amulet options anyway. One other thing to note. According to a poe wiki or something i read that spellslinger always triggers helmet first so there shouldnt be a problem with lightning conduit trying to cast

I need someone to walk me off the ledge. Replace 6 link arc with lightning conduit and add overcharge support to the 3 link arc.