Yes, I have the resistor soldered directly to the first LED Data In lead. I also made sure that the power wires are not looping around the data wire in any way.
I can try narrowing down the LED if possible but they look to be random from that point up.
I reviewed the datasheet (see below) for the LEDs and I think the math checks out for the ls0 value. According to this it looks like should be 350ns, so 14x25.2 gives me 352.8ns
I tried different values just to test and 13 seems to work as well as 15, its just I was not sure that Ls0 was doing anything if I left it at 28.
How does the ls1 value of 28 affect the timing vs ls0?