I have seen waves in Darwin. Would not paddle out though. Stuff that. As for Rote - some great waves. Like all places tides, winds, swell and time of the year play a crucial role. Would love to enlighten you some more - but if you on a boat you will see them. You will probably need to sign in at Kupang though first I would imagine - which will involve some back tracking. Winds between Kupang and Rote can be brisk

. Personally would not be doing that passage from Darwin at certain times of the year without some well thought out alternatives or lots of time to kill