How are people calculating/counting how many ACTUAL ticks are taking place?
Life on hit works best for that.
If you know nothing about a spell, you first need to find out how much life you will gain from one tick. This is essentially your total LoH multiplied by the proc coefficient of the spell. There are lists for the proc coefficiencts of every spell, but if you want to find out yourself, just apply the dot effect to a monster that dies after one tick (i.e. act1 normal zombie).
For example if you do this with 400 LoH and Wicked Wind, you will see 50 life popping up.
50/400 = 0.125 = proc coefficient of WW.
So now you know one tick gives you 50 life. If you want to know how many ticks one twister has, you need a more durable monster. One that won't die before the full duration of WW has ended.
Now you apply the spell to this one and for example at 2 attacks per second, you will see twelve green 100s popping up on your screen. That means your total life return was 12*100 = 1200.
Divided by the life value a single tick gives you, that means the full 6 seconds twister had 1200/50 = 24 ticks.
And that's it :)