Jackson is an excellent signing for Glasgow. I'm actually quite optimistic the way the squad is shaping up, especially around international times. By my reckoning, depending on injuries, we could feild a team with Pyrgos, Horne, Grigg, Johnson, Jones, Hughes and Jackson as the backline. That's pretty strong.
We could also have Kebble, Rae, Allan, McArthur, Big Brain, Swinson, Harley and Ashe available, as well as some (hopefully) very decent youngsters in Hastings, Horne, Cummings and the younger Fagurson. That looks a better second string than we've had in ages, and considering some of them would have been first choices for the national team not too long ago shows Scottish rugby is finally managing to develop a bit of depth.