Root Mechanics

[Shatford]

I've recently started wondering how root works on P99 and haven't been able to find many resources. If anyone can answer my questions, add to the info I've posted, or point me to some quantitative facts, I'd be much obliged.

I'm finding that there is a lot of randomness involved in determining when root breaks. I've been trying the following set-ups.

Root (CLR9/SHM14) - 30 mana - 2.0 cast time
- duration: between 2 and 8 ticks (max 0:48)

Enstill (CLR29/SHM34) - 60 mana - 2.5 cast time
- duration: between 12 and 16 ticks (max 1:36)

Immobilize (CLR49/SHM51) - 80 mana - 1.75 cast time
- duration: max 10 ticks (1:00)

Things that I think affect root breaking:
- difference between root caster's and target's level
- the MR of target
- % to break when a certain dmg threshold is reached (either through direct damage spells, melee critical hits, backstabs)

While nuking down mobs with a Jaundiced Bone Bracer (casts 263 dmg cold-based nuke), I find that no matter what level of root I use, the chance to break remains the same. Here's what I've tried on several hundred level 40 mobs (Raptors in Timorous Deep):

- Tried using Immobilize exclusively
- Tried using Enstill exclusively
- Tried using Root exclusively
- Casting resist debuffs like Malisement (SHM34: gives -37 to MR/FR/CR/PR) and Malosi (SHM49: gives -59 to MR/FR/CR/PR) prior to casting Root, Enstill, or Immobilize.

So my questions are:
- is it better to use a higher level root spell? Are the chances of root breaking less than with a lower-level root spell?
- does using one particular root spell more often improve on greater root success? This seems like a silly question, but it does seem that I have greater success with the level 14 Root more than my level 51 Immobilize. Fizzles, early breakage, and resists happen with less frequency. Is this because I've "used it more" and there's some kind of variable that tracks my familiarity with one spell, and I get less failures as a result? Again, not very scientific in my reasoning, I'm just going off of perception.

Through my experimenting, I've found no matter what combo I use, it seems the chance of root breaking remains the same after the JBB nuke lands. So, in this situation, it is best to use my level 14 Root spell since it consumes the least amount of mana, and it is a relatively quick cast.

If there is anyone out there who has experienced the same, or anyone who can give me a more scientific understanding on how the mechanics of root work?