I have the slits above the door on my classic JP & I found I have to crank the straps to their maximum for the JP to sit at the right height for Jango. I found that by lowering them & putting them in the door, I have more travel in the adjustment on my harness & fits better on my back. The trick is to have the buckle fastener just come out of the back plate so you can access it. On my classic, I have to put on the pack, then sinch up the harness straps & the buckle disappears into my back plate. A real pain in a$$ to put on!