How to shop for a food processor capable of pulverizing plant material to a fine powder?

I would like to pulverize a variety of plant matter (including whole leaves with stems) into a very fine powder. From what I've read, a food processor is better at this than a blender. With the blender I own, I was able to get perhaps 5-10% of the material into a fine powder, with the rest being relatively larger particles.

There are many different food processors on the market, and I would like to know which specifications I should compare in order to determine if a food processor is capable of pulverizing plant matter to a very fine powder, as opposed to flakes or larger particles.

From searching on Amazon, I've found these listed specifications across a number of food processors:

• wattage of the motor
• slice disk
• shred disk
• chopping blade

The wattage is always listed, but I have not seen the dimensions of the blades themselves, only if they are included or not.

I assume that I would require some minimum wattage level, and some minimum combination of different disks/blades.

Additionally, if I fill my blender to the top with plant material, it refused to blend anything. Does a food processor have the same issue?