In short....Pedestal mount are more for stock applications where decking wasn't involved or big profile cams. Easy to install as long as you check the geometry.
Stud are better for adjusting to changes in the engine. You should you use these if you get into custom cams, large heads etc.
The 1.6 moves the valve a distance that equals the lift measurement of the
cam, times 1.6. So the 1.7 opens it a little bit farther.