Assuming that the 65 lbs at 28" is correct, you will be pulling about 62 at 27". I'm not to familiar with the Sky bow, but how deep the shelf is cut will have a big effect on your needed spine; the deeper it is cut, the stiffer the shaft will need to be. Cut to center, add 10 lb; cut past center 3/16" (center shot) add 20+. Using a different method and figuring center shot, I calculate 87 lb spine for a 28" arrow and 125 gr point. A good option would be to contact Sky/Jim Belcher. He knows his bows and should be able to give you some good advice.
You can shoot whatever point weight you like, just tune the bow and arrows to shoot them. At 60+ lbs, you will have plenty of oomph. I prefer the heavier points, 160+, as they seem to shoot better for me and I like the extra FOC. The heavier points do require a little more spine.