All I can say is that Konamix is quite evil when it comes to doubles play 😉. Some songs have a nasty habit of making you go back and forth between the pads many times (era, B4U). Some of the songs are a bit easier though (Super Star lacks offbeat arrows in its doubles version, unlike the single version), but most of the songs are rated a bit higher (there are no 1s, and 3 Basic 7s).
DDR Konamix on doubles
Make sure and get your pads modded, and see if you can get them modded a specific distance away from each other according to arcade specs. It is quite difficult indeed....