Elemental resistance of monsters

I am thinking about how to optimize my character for Merciless and maps. I play a caster, so I often have to deal with high enemy resistance, sometimes as innate attributes and sometimes as auras of rare monsters.

Players have total resistance and maximum resistance. I have 80 maximum, if I'll drink a flask I'll have 90% max resistance. My total resistance can be the same or higher (like 150%), overshooting my max resistance (but it's better to be safe than sorry). So if I'm dealing with 90%max 150% total res, Flammability curse will do nothing. But 20% Penetration will result in 3x damage.

So my questions are: how much does monster actual resistance overshoot their max resistance, if it does? Does Elemental Equilibrium work against such resistance? If I accidentally increase enemy resistance with EE, how much will my damage suffer?

It's important because if resists are like 80/80, it's the best to use a single curse, if it's 100/80 then main attack should be supported by penetration, if max resist overshoots total by 45 or more, then curses are useless without lowering resist the other way (EE or double course)

Could please someone explain to me how this works on monster and what to expect?

im interesring too

I'm unsure if what I'm posting is correct since I've never used Elemental Equilibrium before and I have not tested this. However, Elemental Equilibrium looks like it works like Flammability, Conductivity, and Elemental Weakness. EE in the passive tree states "Enemies you hit with elemental damage temporarily get +25% resistance to those elements and -50% to other elements". I'm guessing this means a reduction in resistance rather than a penetration (since the passive doesn't say "penetrates").

If you have a friend you can test my theory with these builds and a couple low level items with elemental resistances in about an hour. I think you can do pvp against your friend once you reach the forest encampment. Use the character sheet to watch the elemental resists change as you try curses and spells to do elemental damage for elemental equilibrium.

Don't discount elemental equilibrium though. With both the correct Elemental Equilibrium and curse you could reduce even a monster with 150% resist to about 50% which should double your dps against the monster. Penetration will get you an even larger reduction.
http://en.pathofexilewiki.com/wiki/Penetration

Edit: I'm assuming monster resistances work just like player resistances. You'll have to experiment some to see if this is true.