Racking a PDP-11/24

I am wondering if I have racked my 11/24 correctly. As you can see here: https://robs-old-computers.com/2022/02/10/pdp-11-24-progress I have put the CPU at the top and the two RL02 drives underneath. The problem is that the CPU enclosure catches on the RL02 underneath. There is a bit of play in the mounting bracket: https://rjarratt.files.wordpress.com/2022/02/cpu-mounting-bracket.jpg. With a bit of manipulation I can get the CPU to slide in. However, I am wondering if I have racked it correctly? I don't think there is room to move the RL02s down and it would presumably leave a bit of a gap below the CPU. There seems to be very little clearance between the CPU and the RL02 at the front but more at the back, but I am sure that the rails are mounted horizontally. Is it just a matter of tightening the big screws that hold the mounting brackets to stop the play? If so I am not sure I have a big enough screwdriver! Regards Rob