increasing delay time on the Echo Base PCB from musicpcb

[mordechai]

I purchased a great PCB for the Echo Base circuit from musicpcb...and reading through the discussion thread for the circuit, I saw that there is a mod to add a second PT2399 chip to double the available delay time.  I'd like to incorporate this mod somehow into my build.  Can anyone suggest how I can do this with the PCB I'm working with?