Riwaka? Sounds jawanese...
Its a new Zealand hop, I havn't used it before but I think it may be the main flavour hop in one of my fav beers (Kiwi Unleashed by Black Dog) so im going to give it a go.
Still very much in the experimental phase of brewing (just incase chocolate in a pale ale doesn't tell you that) so might end up with a half n half on this batch.