As said, the first board I made was fitted with standard leds (picture in post #12).

But, following a good old swiss habit, I observe and think how to make things even better... and get into trouble.

Frankly, I thought this kind of question would have been common, maybe even boring.

A few days ago, I made a second prototype where I used my SMD NPN's and paired the leds. The visual effect is quite good (will make a video).

Now, if I have to make a third board with MOSFETs, this won't be so terrible (the iron is still hot).

And, please remember Leonardo Da VINCI: he invented so many things but built so few. I try to balance and do the opposite

Many many thanks to all.

NB: "Swiss precision" is not a legend and if you have a closer look to a chocolate bar, you'll notice that even the hazel nuts are lined-up! And yes, I'm a musician.