For the distances you are considering now, the Encore is more than sufficient.
Neal gave you the versatility of the Striker already. He has had great success with them, and will give good counsel if yo go that way.
If I went with the Encore I would have MGM build a barrel for me that I wanted.
I personally do not like the trigger on the striker when it is in its mid-grip stock. If you went to a rear grip you have better trigger options.
Are you wanting this just for shooting, or would it involve varminting and big game hunting?
I use XP's (center & rear grip) or the MOA Maximum. MOA Corporation Homepage
The XP-100 which has a RH bolt is perfect for a lefty like me, and I just like them.
There are a number of ways to "skin the cat" when it comes to long-range.
If you could get with someone who has some experience at shooting distance your comfort level at shooting further, would increase quickly.
Welcome to the world of specialty handguns!