I'm considering mining on a decent hash rate pool in order to reduce my variance, but the nearest I could find was in the US and Europe (about 8000km each).
That means there would probably be a network latency problem.
Why do you think there would be a latency problem?
Probably most of european miners use US based pools, and there's no latency issues. In fact, running your own p2pool node is probably worse if you've got a bad internet connection.