I use extra-coarse and coarse DMTs - on my third set now and for this reason I always recommend lapidary grit on a plate of glass or granite for initial truing of hard-to-lap stones, followed by the diamond plates for finishing off.
Contrary to what has been said above, the sticking issue holds true for every fine-grained stone or hone I have ever used a diamond plate on (includes DTs, thuringians, welsh oilstone, CFs, naniwa super hones, shapton glass stones, 6k King hones and others). If it's not an issue it generally means it is a very coarse-grained stone or you haven't even got anywhere near finishing lapping. I find (other peoples experience may differ from mine, of course) that once you are 'nearly there' then five or six laps causes the stones to stick together - forcing a few more laps makes them stick alarmingly - enough to damage the softer hones like naniwas if you aren't careful getting them to part company. You can avoid most of the 'stiction' issue by lapping underwater (dont use the sink - those plates can crack a vtreous sink in no time - trust me, I know!) - a washing-up bowl is a much better idea, or on the draining board of the kitchen sink with a tap dribbling water on an exposed part of the hone as you lap.
I finish nanis and shaptons with a shapton plate now - it has a ridged construction so sticking is not an issue. When I have worn out the DMT I will try the non-continuous surface as suggested above for this reason - sound advice.
Regards,
Neil
