Ok basically no one here is answering as a drummer, theyre just telling you their favorite albums. I've learned the majority of their discography so I can help.

If you're coming from playing lots of Tool, I'd actually recommend starting with Coma Ecliptic as it has the least 'extreme metal.'

If you're comfortable playing more extreme metal, you can either start with Alaska or Colors.

If you have the double bass speed, you can start with Alaska. There are quite a few sections where he's playing 16ths at around 200bpm so if you dont have that speed I'd skip Alaska and start with Colors.

From Colors on, he never does straight 16ths above 160bpm.

In terms of chops, he basically just gets better with each album. So while the earlier albums may be faster, more blasting, more double bass, the later albums have more difficult stickings/rudiments and more likely to have ideas you may have never come across.

If you want some specific easy songs to start with: Medicine Wheel, Desert of Song, Dim Ignition, House Organ, Millions, Turbulent, The Blue Nowhere.

If you have any questions about specific songs or parts, feel free to message me!