The N3DS_roploader is the one you want on your dstwo, the other roploader is for the o3ds, just use the n3ds roploader and select the first option and you have reinstalled the mset exploit.
Ok so that's it? No formatting my NANDs, no installing DevMenu, none of that? I just run that N3DS_roploader.nds on my DStwo in my n3DS XL and that's it?