I don't know if the blinking light brightness can be changed in the kernel. Would be a cool mod if it could be.

My work-around on my Mk1 was to make the light smaller by doing some heat-shrink tubing around it (being careful of the VFD and its fill nipple). Now my Mk1's LED is a tiny itty bitty little light that you can barely see. This was necessary since I now have it mounted next to my television set and it would be distracting at its original brightness.