Hi Chris,
That is a possibility, however if you look at the last pic, that distance between the glass and the window, is an inch at the very most. Therefore, combined with the distance from the front of the window and the girder obstructing the access, makes it more difficult. If that roof was further away from the window, I would be able to slide a applicator up there. I'm once I'm there I'll suss it out, I'm just trying to think ahead though! Cheers