Tim Watts wrote:

I was going to add, before my finger hit send - I wonder how long a
strip you could run before the data line gets too corrupted.

I think there's no absolute limit, my strip of 144 (not 200 like I
though) takes 75mA for the inbuilt chips with all pixels off.

Each pixel regenerates a clean version of the pulse-train to its
neighbour, in my case the limit is the USB block size, once you hit that
you would get a long enough gap in the pulses that the pixels at the
"head" of the chain would start listening for new colours, rather then
silently echoing them down the line, which is how you start a new "frame".