Not yet. I have both in stock and Im planning a southern hemisphere style IPA using Riwaka as well.
Heres my experience with all three of these NZ/Aussie hops...
Nelson Sauvin - It really does mimic NZ sauv blanc. Big grapefruit zest, a little grass, a lots of tropical fruit notes. Very similar to passionfruit, mango, and maybe even a little pineapple.
Galaxy - Similar to above with the Citrus being just a little more dominant than the tropical fruit, but both are there. Very similar to citra.
Riwaka - Remind me a lot of centennials. Grapefruit and very floral.
heres my planned recipe
OG - 1.066
FG - 1.012-013
ABV - 7%
IBU - 69
1# flaked wheat
1.5oz Riwaka 5.8%AA FWH
.5oz Galaxy 14% 60min
.5oz Nelson 12% 30min
1oz each Galaxy and Nelson KO
.5oz Riwaka KO
ferment with s-04
Dry hop with same hops and amounts as KO addition
The plan for the hop profile is to really feature the tropical fruit notes as well as the citrus, with the riwaka adding a little background floral note. Obviously I havent brewed this yet but Ive brewed similar nelson/citra beers.