I've been researching this for quite sometime working with a Noritsu and a Frontier. This is what has worked for me.
If you edit in AdobeRGB you'll need the full version of
PS to do conversions or if you're on a Mac there are scripts you can find on the most Mac install CD's in the Colorsync Extras folder that will do the conversion if using Elements. Look for the script that says Matching in the name.
That said no matter what profile you get all of these printers will drift in color cast tint and between models and paper types will have varying grayramp density distribution characteristics that won't match exactly your 2.2 gamma grayramp. It will be evident in how shadow detail ramps out of black and highlites get blown out from white.
The cast drift will be most pronounced in fleshtones and mid grays and change within a week's time. Other primary type colors will look pretty much the same. The casts in fleshtones can go from yellowish orange to maroonish to bluish to greenish depending on the model and locality. At low volumns during the week it could be yellowish orange at high volumns like on weekends maroonish blue.
But it's consistant. The Noritsu I use locally has drifted this way for two years like clockwork where I have two DryCreekPhoto.com profiles that emulate these two casts by temporarily assigning it to an sRGB test file I had printed with no operator color corrections. The sRGB test target consists of a grayramp and gradients of the six 255RGB display primaries and several indoor/outdoor bridal photos of varying fleshtone colors. The assigned profile that makes the test image look like the print is the one I convert to from AdobeRGB. You must have an accurately calibrated display to get this kind of precise predictability. Eyeball calibrators aren't accurate enough if you have an LCD.
Editing in the printer space by loading it in Color Settings or assigning it to the image will not guarantee the best results because you won't know which way the printer will lean that day and you can exaggerate the misalignment by editing in the already bumpy fingerprinted environment of a table based printer space. To see what I mean assign the printer profile to a grayramp and notice the banding and color crossover anomolies. It's a nasty space.
There is a generic clean table based printer profile called PhotoGamutRGB on the web that takes advantage of these types of printer's gamut while maintaining perfectly neutral grayramp when assigned to an sRGB image. It can also be safely used as an editing space, but if you send that file to a printer that isn't as prestine as this profile you might get unexpected results just as you would sending sRGB. It might be subtle or it might be glaring. Always run a 4x6 sRGB test print and assign your printer profile to check for differences.
However, if you're not too picky unlike me and you don't mind fleshtones without a color cast just sending an sRGB file may suffice. It's hit or miss, though.