You will need a ruler foot, but Janome has a great one. Definitely get a straight ruler, one that is not too much longer than your hand. A longer ruler tends to bump into the edge of the harp if it is too big. Either of the two that have the straight sides from the ones you mentioned would be good.
I like Archy a lot. It can be used for many designs and is a good size for a DSM. Someone also mentioned the Versa tool which is a great ruler. Be aware that ruler work will take practice. Start with the straight ruler until you get the hang of moving quilt and ruler together. Curved rulers take more practice but can be used in many ways. Don’t get discouraged if your first efforts are shaky. Just keep trying. It will click and probably sooner than you expect.
Enjoy!