Blue LED's for flashing LFO's (resistor choices)

[80k]

Hi,
I've used blue LED's and just used higher value resistors (around 4k7) with a 9V battery with good results.

But when the LED is flashing and the setup is more complicated, i'm wondering how to calculate safe resistor choices for it.  For instance, in the 4ms Atoner, it has the LED in parallel with a 330 ohm, and in series with a 470 ohm going to ground.  THis is for a regular red LED.

Picture here: http://img111.echo.cx/img111/2143/ledsetup2ci.jpg

How would i calculate what to use with a Blue LED based on a setup like this?  Thanks for any guidance you can offer...  Dann (the designer) says that he usually just takes off the resistor in parallel and it works great.  But i'm wondering about some more info on how to calculate this, so i can better understand it.

Here's the full circuit.
http://www.commonsound.com/atoner/atonerbig.pdf

Thanks!