[tor-relays] Some n00b questions about exits

I'm thinking about running an IPv6 exit. I've found a Tor-friendly VPS provider, but they have metered bandwidth. And 500GB per month is about my limit. So I could have a 40Mbps/80Mbps exit that was up for maybe a week per month, or a much slower persistently stable exit. For exits, speed is better than persistence, right? Also, I can choose VPS in UK vs DE vs US. Which is needed most? And am I right that a DE exit will generate the least hassle? Thanks.