What is the lower limit cap of "+%x to y damage" in total for ultimate?

As far as i know +%1000-1100 total seems enough depending on data that are posted on build section for each.

What do you think? Many builds specializes on two damage types and total of %1800 bonus for both seems good i guess?

A build has +%1300 fire and +%500 other.
+%1000 and +%1000 chaos total, how does it look? Probably, this is not good since you sacrifice survivability for this.

So is there any actual lower limit? Depending on some items and constellations, some damage types could be more in the late game than others.
Does anyone have numbers?

You can’t tell without the list of all the resistance reduction you may have.

Indeed. As a super tanky witchblade i was critting over 50k with a mere 600% physical damage (and a lowly lvl 22 guardsman mallet) because of massive res reduction. That is enough damage to clear ultimate, albeit slowly. Although 1000% chaos might easily feel slower in many areas if you lack good res reduction. So the number could vary wildly. Although most of my builds that do ultimate end up with around 1200 to 1400 after counting for spirit.