Tim,
If your coticule does not produce slurry easily and it does not turn grayish from metal particles, than you have one of the slower stones. With some coticules, the rock that bonds the garnets together is so hard that it's difficult to raise a good slurry. With other slow coticules, the garnets themselves appear to be slower. From the information you provided, my bet is that you have the former case. Probably a great polisher, but not much of a metal eater.
But, my friend, do not despair, a stubborn horse often rides better then an indulgent one, once you learn how to tame it. :-)
First off, your hone should indeed be absolutely flat. If not, you need to look up Josh Earl's tutorial thread for lapping hones, and get it properly lapped.
Here's your new improved slurry raising recipe for callous coticules: fold a piece of 220 grit (other grits might work too) sandpaper around a small wooden block. Use that sanding pad on a dry coticule (that's right, no water, not just yet). Sand the entire surface till it is covered with fine coticule dust. It won't take very long. At this point, add a few drops of water, and use your cotigura stone to mix the dust with the water to a rich slurry. Add more drops of water and smear till you're happy with the consistency. With this slurry you should be able to remove metal and witness how it darkens to a rich gray, within 30 to 50 honing laps.
Should your stone be the latter case (slow garnets), than, no matter how nice a slurry you raise, it might take hundreds of laps before you start noticing the presence of metal particles in the slurry. While such stones might very well be even finer polishers, you won't be able to cut a good bevel with them. In that case, it might be better to use it only for finishing the edge and do the preceding honing part with another hone such as the DMT1200 or the Norton 4K before you jump to your lazy coticule with slurry and finish with only water.
BUT... you can also cheat that coticule into thinking it is a fast cutter. :-)
Get yourself a lightning fast and soft cotigura stone (cotigura = the little piece of coticule that you use to raise the slurry). Throw away that sandpaper and rub with your cotigura on your coticule till you have the slurry of your dreams. 80% or more of that slurry will be produced by that cotigura, but who cares. Your razor doesn't.
If you're interested in such a superior cotigura stone, PM me about it.
Hope this helps,
Bart.