What I did for glass to window frame was use a razor knife to cut the old ragged gray seal back, then taped the glass and frame and used Vulkem. You can use Vulkem or Sikaflex interchangeably. My understanding is that Acryl-R is for smaller cracks. However I bought a new Vista View from Airstream that leaked between the glass and the frame and they suggested using the Acryl-R to seal it up. (QC is still an issue...
) Someone here has taken a window apart and rebuilt it using a black seal to replace the gray stuff, this is an involved process and not for the faint of heart!
Aaron