I just figured out a way to be able to remap all 6 pages of Dicer on Mac.

With Serato closed go to Applications > Utilities > Audio MIDI Setup, once there go to the MIDI Studio window (if it's not visible go to Window Menu > Show MIDI Studio).

There, you should have a block diagram of MIDI devices you've connected to your computer. Look for Dicer and double click it. This should open a window with further info on the device. Go to Device Name and change the default "Dicer" to something else (eg. TheDicer). Quit Audio MIDI Setup.

Launch Serato and go to Setup. Under MIDI you should see Dicer as a new MIDI device with the name you gave it (eg. TheDicer Novation Dicer). This means you can remap it now completely. Only caveat is that every light will be green, but works great for simple mapping that don't need much color feedback.