Atoma 400, DMT 325, or CKTG 400/1000 for lapping

I've been using the sandpaper routine to lap my Naniwa Super Stones and a couple other stones I have. Its getting a bit annoying and I'd like the convenience of a diamond plate. I have done a lot of searching, and don't know which would be best, and what grit.... I've been contemplating DMT 325, Atoma 400, and the Chef Knives To Go 400/100.
 Do I need 2 grits? Like a finer grit for finishing stones?
 Any input is appreciated!

I've always used the DMT 325 (coarse) Dia-Sharp to lap Naniwas.

I actually like the finish that sandpaper puts on the stones to finish them with, but I do use Atomas to lap, usually a 1200. I don't let mine get so far out that I'd need a 400 though rarely I have used a 600. The DMT 325 when it's worn a bit puts a nice finish on the stones for it's grit. The Atomas have raised 'dots' that make scratches seemingly coarser than the grit, but the Atomas don't stick to the stones like the DMTs do because of that. Never used the CKtG plate though it seems to attract faborable comments.

Whatever plate you end up with, keep the slurry rinsed off it or use it under running water. A thick, pasty slurry can ruin at least an Atoma, I did that once.

Cheers, Steve

I own a few diamond plates, but my favourite method would be good quality 400 grit wet & dry out the back yard on my marble slab and a hose pipe just prefer the speed and finish personally.

I have the Atoma 400 for the heavy lifting and a couple of DMT 325's, a new one and one that's about three years old. The old plate is mellow and puts a nice final finish on my stones. On certain stones I still use W/D on a granite plate depending on the final finish needed.

I use a Atoma #400 for lapping then I have an Atoma #1200 plate stuck to the back side of the 400 so it's a duel purpose plate and the #1200 works really well to burnish after the #400, I also use the 1200 for slurry generation.