help with passive attenuator values

I have a theta gen 5a with 3.5 volts and either 35 ohm (manual says)or 60ohm (wedsite says) output and wish to have attenuators installed in a pair of cary 805c. I am confused at the correct value 10k,50k,100k? Kirk at cary has says a 100k would be correct but his front ends all have high output impedance. My solid state front-end does not! As they say, measure twice and cut once. I hope someone has experience with this and will help. Also is goldpoint the kind.
If they're going to be installed on the amp chassis you'll want 100K pots as they will replace the input load resistor.
I agree with Citation. However, if you are going to use it as external passive attenuator, you will need a 10k attenuator.