Zepplin,
I've talked with Howard in the past, and I just double-checked his site . . . he recommends that the DMTs only be used to flatten your whetstones, but not to use them directly on straight razors.
That said, if you check DMTs' website, you'll see that the D8C (325 grit)
and D8E (1200 grit) have a continuous surface
http://www.dmtsharp.com/products/diasharp.htm
However, the W6EP is a perforated surface
http://www.dmtsharp.com/products/whetstone.htm
that would not be good for a straight.
I'd stick with Howard's recommendation and at least avoid using the perforated whetstone on your straights.
YMMV
Tom