First off I don't like the pellets. they are too fragile and unrealiable. Now this is just my opinion so take it for that.
I don't like taking any long shots with my ML. But I will go out to 150 yds. max. My problem with these shots is that the drop is so great, it gets to be a pain in the ass trying to figure out my shots in a situation that doesn't give me much time to do it in. Another thing to consider is that here in Virginia I don't get a lot of opporrtunities for the long shots.
Now if you are sitting on a field up there in NY, I guess I would work out combinations for these long shots. If you are in the process of doing this I would look at the Black Horn 209 powder. This powder does operate at higher velocities and this may be what you are looking for. I would give it a try.
Good luck on your task! Make sure you get back with us on your results.