with the pioneer cueing method I mean that u cue this way:
push pause, search your point, press CUE (instead of play)
This is just a personal thing, I like it because I'm used to it
The beat cutter is controlled with the buttons on the upper-left side of the CDJ-800.
When you push '8' you get an 8 beat loop
then you push '4', the machine shortens the loop to a 4 beat loop (loop in point remains the same, out point is adjusted)
then 2, 2 beat
and one one beat...
There also an other way to use the function,
You make a normaal loop (loop in - out)
the '8' button resembles the whole loop,
when u push '4' the machine cuts the loop in 2 (again, the in point remains the same)
the 2 button splits the loop in 2 parts again, and the 1 button does it again...
Really nice trick to do (you can also do it with the hot-cue's from the cdj-1000, with some imagination

)