Barikobart. First I'll echo the others above by saying that is going to be a lovely room, with a MARVELOUS view. Very nice.
1) It's possible you may have to angle the VP150 down a bit, but it's not a certainty, and I'm leaning toward th probability that it won't be necessary. It's gonna be one of those "you'll just have to wait and see" things. Depending on how you will be mounting the VP150, angling can be very easy. If it's on a shelf using a couple of those wedge shaped rubber doorstops (or any nicely finished, wedge shaped, pieces of wood) can easily do the job. If they would be hidden from view, the doorstops work fine.
2 & 3) The consensus optimum height for the M60s is having the tweeters right at ear level. But, that is the ideal. When it comes to placement, many of us are unable, for one reason or another (space constrictions; furniture configuration; "significant other" demands, etc.) to achieve the ideal. I have my M60s on 13 inch risers, and sit a lot closer them than you will be to yours. No problems.
Just try to be sure the front edge of the M60s are out from under the mantle an inch or two so as to avoid any reflections off the bottom of the mantle.
My only concern about your proposed placement of the M60s is that they will only be about 8 feet apart while you are sitting 14 feet away. As you can see, from the diagram below, the optimum is for the speakers to be as far apart from each other as you are from each speaker - the "golden triangle." For that reason, you may want to experiment with placing the M60s on the floor a little wider apart. Again, this is an ideal which many of us are unable to achieve. Doesn't mean you proposal won't be satisfactory. Experimentation is recommended.
Glad you're here. Keep us posted on the progress of your house, and what you decide to do concerning placement. Enjoy!
