The % of cap at time of signing shows that this is a good deal. He could have a poor year next year, but that can be said of any player. The key is getting a guy like him that you think is your #1, and has performed as such, locked up long term at a very good rate.
The backup situation is not ideal IMO. But that is not solely the fault of Helle making 6M. It's a result of the cap crunch the entire team is facing. Ideally, I'd feel much better going into next season with a much better backup. Realistically, I'm not sure where the cap space would come from to make it happen.