This remix gives additional clearance on the sides of the top carrier so they do not rub against the bottom of the build plate heating element. It moves the side screw mount points down by 3mm.
Also, on my printer at least, the change makes it so you can't over-tighten the top carrier. Just screw it down all the way as tight as you want, and the spacing appears to perfectly match the 8mm smooth rods (due to printer differences, your mileage may vary).
You will need to use the bottom piece from the original
You will need to raise up the idler bearings, stepper pulley and limit switch. To raise the idler posts I simply added another 608zz and removed the lower large washer because it wasn't needed. To raise the limit switch I used some washers to raise it up and also glued a bit of plastic to the lever arm to make it taller. Raising the stepper pulley is easy: just loosen the set-screws, move it up, and then tighten them again.
I am using cheap bearings from Amazon, even though I'm not supposed to :) Because you can't over-tighten the top block, I hope that the cheap bearings will still work in the long-run.
The included .zip file has the openscad files, as well as the top piece from the original.
Must use support.
Use bottom piece from original.