I wouldn't recommend getting anything printed through Moemarket, CuddlyOctopus is cheaper, will print your daki on better material, plus they won't steal the art and post it on their site for reselling (if you care about that).
That being said, the numbers are not a bad place to start. The best thing to do is to email wherever you're getting your daki printed and ask for the margins. You don't want to get a daki drawn at 160x50cm, you want it drawn at the margins the printer recommends. For CuddlyOctopus, I think this is 166x54cm, but I'm not certain.
In my personal experience, ~150 dpi is plenty for print quality, but I'd check to see if the artist is willing to draw it larger, as higher resolutions can't hurt. I think CuddlyOctopus only accepts print files up to 20mb though, so anything much larger than ~200dpi will probably not be printable.