no save way to see, since there is no debuff icon on mobs with a counter.
But per math its fast forward, lets assume you have 25% Aliment-Chance, just as assumption. that means every 4th hit applies alimentstacks, with the Doubling stacks passive and the apply 2 stacks passive it goes like up like this:
2
4+2
12+2
24+2
48+2 But well pointless you reached 30 stacks. now you can kinda assume that you need 5 aliment stacking attacks if you take all of that.
If you dont take the do 2 extra stacks ofc i take way more hits and alls i coupled with your aliment-Chance but as rule of tumb, skill that hit multiple times apply better and faster. 30 Stack in 1 cast of Wailing Arrows or Tear with Fire Mod is easily achived.
HINT: If your aim is to deal the most dmg with Aliments. Go for Crit-Chance and Aliment Chance not just aliments, the Dmg Multiplier throu critical Aliments is to massive. As your Example 7500? multiply that with your average Crit of 300-500% and you have some serious hits. Als make sure to kinda get a focus, getting dmg all over the place wont get you as far.
Also if you can apply the Aliments on Aoe, focusing on Bleed or Fire gets best results because they have higher tick rate. Bleed ticks every 0,5 Sec and Fire every 0,6 Sec, meaning in the a time frame of like 3 Seconds Bleed will hit 6 times and Fire 5 Times. Shock for example only ticks 1 per second so 3 hits.