Passive crossover design

For a passive 12dB/octave resistor capacitor crossover for use between two tube stages how do I design it?

Is it select a resistor and capacitor value and multiply the result by 10? If so do I put the smaller value first or the larger value first?

I know for a high pass the capacitors go in series and for a low pass the resistors go in series.

I'll post the schematic of what is driving the filter and the stage after the filter later in the morning when I get to work.