I'm looking for a safelight filter which cuts out all wavelengths below 725nm. I guess Kodak #11 lets through everything over 800nm but I'm hoping there's a filter that passes more of the red between 725 and 800. Does anyone know of such a filter and where to buy it?

Thanks.

Look in this document. You should find what you want here:
http://www.kodak.com/global/en/professional/support/techPubs/ti0845/ti0845.pdf