The market price on Poloniex is currently 0.000496 USD for NSR and around 0.20 USD for US-NBT. That would imply an NSR market rate of 0.00248 US-NBT. I would suggest a practice of setting the reserve price 10% below the market price, which is 0.00223 US-NBT in this case. If NSR isn’t purchased because of the reserve price, then we are better off selling the NSR on Poloniex. Whatever isn’t sold in the auction should be sold on Poloniex.
One hazard of picking reserve prices is that the market rate of NBT or NSR could change before the auction ends, which would make the reserve price suboptimal. I don’t see a good way to remedy this, although it is possible to do so by selling only on Poloniex where reserve price doesn’t apply. We can look at the results of this auction and decide whether it makes sense to have another auction or sell on Poloniex.