understanding watts vs volume

[DJ Matt]

I'm looking at the specs for 2 different speakers here, as follows

Yamaha DXR10 MKII - 1100w - 132db - €619

Yamaha DBR10 - 700w - 129db - €399

I appreciate that wattage is not always a good indicator of loudness, but in this case they are all the same brand so i imagine the build quality and efficiency is similar across the different models

so, my questions.

am I going to notice much difference between the volumes here? I believe every 3db is technically twice the volume right? so, the top one is twice as loud as the bottom one? or is this just theoretical, but in reality the difference would not seem like all that much for a speaker that is twice the price
Iv used the lower one and its loud for its size, I have to say

or is it a case, i basically wouldn't have to turn the volume up so much, so the speaker might last longer? does that even matter with pro speakers?

oh and one more question
Yamaha DXR15 MkII - 1100W - 134db - €929

how is this 15" one able to hit higher volumes using the same wattage as the smaller 10" one? i would have imagined that the smaller one would be able to get louder given the same wattage because its smaller, less work for the watts to do ?