Thanks for the positive response!
Let me try to answer some of your questions.
"You mention both position lights (for the rear) and tail lights. Are they the same thing? We have discrete position lights on the front of ST1300s but not on the rear."
Now that I look at it, the wording might be a bit confusing. I tried to use the proper terms (as found in the Wikipedia article on automotive lighting), but not being a native English speaker I might not have used the most intuitive terms. With position light I mean the big red light, with tail light I mean the entire unit consisting of indicator lights and position/stop light. If you can suggest clearer wording, please do!
"As a personal preference mine is for a 'smooth' blanket of light from an incandescent instead of the multiple points of light from an LED array. Would doubling the density of LEDs be doable? And adding a diffuser? I realized the current values would be different."
I agree with the smooth surface, that is what I was aiming for with this build. The only other led tail light unit I've ever used had this done very nicely. My guess would be that it has to do with diffusion. The lens on the led unit had all this tiny pyramids on the inside, the lens for the bulb unit didn't have that. Short of making your own lens I don't think you can easily reproduce this effect. Putting in another type of diffuser might work, such as some white plexiglass. I don't have any and find the current smoothness good enough, but it could be a path worth investigating.
Doubling the density of leds should not be a problem. I've spaced them quite far apart to limit the total number I put in the tail light, but you can easily put 2 or maybe even 3 times as many leds in. If you move the current regulators to the bottom or the side, then you can fill the entire surface with leds. This would also give you the option of going brighter if you like, but it would also be a good take on the smoothness. Total light output is a function of the current. As long as you don't change the values of the current source you'll get the same light output no matter how many leds you put in.
"I've replaced the incandescent bulbs (except for the ST1300's two position lights in the headlight assembly) with LEDs. They don't illuminated the lens as evenly as incandescents but they're brighter than stock."
Not all led bulbs are created equally. Some have leds on only one surface, some have them all around. The results of retrofitting these vary with how the lens and reflector respond to this. Actually, this is one of the reasons I decided to put in a led board instead of only swapping out the bulb.
"I lack the patience to test determine and configure such an array but I can solder."
If you are confident that you can build from a schematic diagram, you can probably make your own. The design work is already done. But if you're unsure, you might not want to experiment too much with something so essential to your safety in traffic.
If people are actually interested I might design a pcb (printed circuit board) after all. That would make it easier for tinkerers to build their own
Cheers,
Maarten
