Gearsack Rack

Hi again. Been a while since I've been on here.
I'm in my final year of a teaching degree, and decided that I'm probably going to need a way to cart all my books to school and back so I started looking into getting a luggage rack for my gpx 250. From what I could find out, the Ventura racks were going for about $300 - $400 but I managed to find secondhand gearsack rack and bag for $50. I hear that they're better/stronger anyway?
Just wondering if anyone here can tell me how to go about sticking it on the bike, pics would be great if you have them. The guy at the shop reckons it'll fit, but I might need to do some bending to get it all snug?
Did I make the right choice in grabbing it straight away?
I'm in my final year of a teaching degree, and decided that I'm probably going to need a way to cart all my books to school and back so I started looking into getting a luggage rack for my gpx 250. From what I could find out, the Ventura racks were going for about $300 - $400 but I managed to find secondhand gearsack rack and bag for $50. I hear that they're better/stronger anyway?
Just wondering if anyone here can tell me how to go about sticking it on the bike, pics would be great if you have them. The guy at the shop reckons it'll fit, but I might need to do some bending to get it all snug?
Did I make the right choice in grabbing it straight away?