The crystarium one was easier for me, I actually went all the way to the top of the tower and walked (used the keyboard input to lock my character in "walk mode") off the edge above the vista. It did take several attempts to figure out the exact point, and even had one instance where my character landed on the point but slid off slightly so I was outside the vista range... and when I attempted to correct I then slid off completely. At any rate, both of these are way easier than Kugane Tower madness.