pigment milling

I'm an oil painter and I grind all my own paint from scratch using a glass muller. I'm looking into the idea of using ultrasound to break the pigment particles into smaller sizes and to help disperse them in the oil, which will increase the vividness of the color.

I've seen slides of ultrasonic milling here:

http://www.hielscher.com/ultrasonics/mill_01.htm

But I don't know how much power it takes to do this or whether it's feasible in a batch of, lets say, 200mL. They have devices from 50w all the way up to 16kw and operating in the range of 24kHz-30kHz

Mineral pigments such as iron oxides and titanium oxides can be dispersed using this method, but at the density I require for my oil paint I wonder if the ultrasound can penetrate well enough. I'm ordering an ultrasonic cleaner from ebay to run some tests, but I wonder if it will be strong enough at 35 watts or if 42kHz is too high a frequency to be effective.

Does anyone have experience with ultrasonic milling?

thanks for your help