A DMT1200 will be enough to reset the bevel on a very dull blade. Are you looking closely at the blade under magnification? That's a wonderful way to see if what you're doing is having any effect. I use a Radio Shack Illuminated Microscope for $10 and it will inform your honing big time.

You can go DMT1200, then a belgian blue 4000 then a coticule 8000 and then strop. Or you can go to a Shapton 1k, then 4k, then 8k, then 16k and you'll be shaving fine. I didn't even need to strop after the shapton 16k.