Hi, been mining with your pool for a few days and getting some nice payouts

Can you clarify how to configure scrypt for backup pools though? Can we just use the --failover-only command as with cgminer?
https://nicehash.com/index.jsp?p=faq#faqs1Who is the hash provider? You? Also whats the minimum and maximum hash power? And whats your refunds policy? Say rig was offline or hash less then promised.
Everyone who has a mining rig can be hash provider. There are no limits of minimum and maximum hash power. As a buyer, you only pay for valid (accepted) shares. If rig is down, it sends no shares -> you pay nothing. If rig is underperforming, it sends less shares -> you pay less. Simple as that.
Now it is more than 30 already.

How is this service not 10GH already

Not many miners see the full potential and all benefits yet.