You are going to want to max your iron golem and maybe even toss 5 points in clay. While the points in clay won't really be needed for the optimized build, you are going to use clay on every boss or big nasty champ that you take on and you need to be sure that your clay lives long enough to hit the boss and trigger the whopper slows target effect.
The "dance" for boss fights is as follows:
1. Get him under control with Iron Golem/decrep
2. Pop up a clay golem to further tame the beast
3. Hit them with Lower Resist
4. Stab with psn dagger/wand
5. Switch back to Decrep
repeat/rinse until boss dies. Having a long poison duration on your dagger is super handy as it means fewer times that you need to run up to the big mean boss with your skinny bony ass.
The reason you can keep decrep on a boss is that the psn damage is calculated at the point of strike and is then unchanged. So if you hit him with Lower Resist is on, your psn dmg is calculated then and stays fixed for the 10 seconds that hte psn runs its course. So you might as well switch to a more useful curse for the remaining 9 seconds. Decrep is probably your best bet for keeping the golems alive.
Here is a video showing what I am talking about:
http://www.youtube.com/watch?v=mTpOKwNb ... re=related