As far as Narcisse Noir, you can get samples from Caron for $5 each. Their telephone number is: 212-319-4888. The sales people are very nice (at least that has been my experience.) You can even try NN in parfum concentration- probably in all the different concentrations if you want to..
As far as liking both Coco and Narcisse Noir- it's impossible to tell. I know Tigs likes both, however I really love Coco but wasn't moved by NN. They are both rather dramatic fragrances and I think you need a bit of "personality" to pull either of them off. Past that, all you can do is try them on your skin and see what you think.