Or as I said, just stick in standard red LEDs.
I've replaced LEDs many
times
without thinking what I am fitting.
"without thinking" is that an impostor pretending to be Tony? :-) :-)
No, it's much the same way that I breathe without thinking. It is
something that doesn't need thought.
The 'bog standard' LEDs I get from Farnell, etc don't seem
ridiculously bright when used with the same series resistors
I was using 30 years ago (say 330 Ohms for an LED from
a TTL output to +5V, giving a current of around 10mA). I
suspect others are right and they would look odd if mixed
with old LEDs on the same panel, but if you are replacing the
lot it won't matter.
As regards the long lead issue, you can of course solder
extensions to shorter LED leads. And if you find you need
more series resistance, one of the extensions could probably
be a resistor.
-tony