i can imagine that you have to use more leds to get the same optical performance as when you would have placed the leds against a transparent edge, coz, correct me if im wrong, the drilled holes are a bit diffuse and therefor create less bright blobs
I also cut off the head of a led and glued it to the acrylic with epoxid resin, this way it seems as if the led and the acrylic were one peace, i guess I should get quite nice result with it. Here some pics:
the amount of light is amazing! what kind of LED did you use?
doesn’t get the angle of the LED too big when you cut the heads so that you loose sight through the surface of the acrylic?