Purifier firestrike and WPS interactions

I’ve read some of the ongoing threads (including some discussions in the class/builds section regarding how some of the Firestrike line interacts with WPS) There’s some change in the recent patch as well as some old questions which i had WRT how damage and other mechanics are calculated wrt Firestrike/WPS interactions, mainly with purifier builds.

  1. Firestrike has about~122% weapon damage. WPS typically has some % weapon damage. From what i understand, if the WPS has X% weapon damage, u basically multiply the 2 and get the final i.e. if it’s 122% firestrike, the WPS is 200%, u get 244%. Flat damage from adds on top of that, so from what i understand is, explosive strike’s physical, static strike’s proc, etc, are all going to apply to each shot, of say, jaxxon’s lucky shot or storm spread. From what i gathered, explosive strike’s 30% add to each individual storm spread bullet as well. Is that right?

  2. Weapon damage mentioned above i assume is the number that appears on the second tab of the status screen under weapon damage? Or is it simply the numbers on the weapon itself? Also, for WPS that fires off DW pistols, if the animation shows one pistol, i assume that only one flat damage instance is applied, and if the animation shows both, then the flat damage instance is applied twice (from both weapon damage being calculated?)

  3. Dagallon’s helmet was reworked to convert chaos into lightning/fire on firestrike. I assume it’s safe to say that all chaos is converted, even from brimstone, or if the weapon itself is chaos damage (e.g. bloodsworn repeater). What about chaos damage from seal of the void and the likes?

  4. WPS/ADCTH interactions. How do sub-100% WPS interact with ADCTH? As far as i understand, the amount of % that ADCTH drains is dependent on the weapon damage % of the attack or skill that is being done, i.e. WD%*ADCTH%, capped at the ADCTH percentage. What about, say, a storm spread on a firestrike attack, do i get:
    a. 33%*adcth%
    b. 33%*1.22(firestrike)*adcth%

Would need some help here with these questions. Some of it i have no idea how to test on my own like in the case of ADCTH as well as damage conversion. Thanks.