If the amplifier document mentions the name Boucherot Cell, then I'd have to guess you're making a TDA7294 based amplifier? From practical application, those seem to appreciate 4 ohms or larger values because that chip will automatically step down the output power in presence of a stronger load.
There is a great debate about the resistor value. The value of 2.7R was published in National Semiconductor documents for their Overture amplifiers.
Some believe that the value is a mistake, some believe its audibly harmful to sonics, but I beleve that the intention was for large scale production to use an extremely economical polyester capacitor's typical very high ESR (internal resistance) in addition to that 2.7 ohm resistor.
There is, however, no guarantees on satisfactory audio results with 2.7 ohm resistors in amplifier speaker output zobels.
That's because the average ESR approach doesn't indicate any reliable figure during a specific bandwidth (like your upper treble that may get brutalized because the appropriate amount of additional resistance did not occur at that specific bandwidth), so however you look at it, 2.7R (and smaller values) could be a blunder.
One sure-fire solution is to measure the DCR (reference load) of your current speakers. For instance, 8 ohm speakers probably resist DC at 6 ohms. You can use that as a resistor value along with polypropylene (MKP) capacitors that are currently in style. Thus, the wikipedia value of 5 ohms is very close to generally good.
Capacitor values include 0.22uF, 0.1uF, and 0.047uF. Given that one wishes to avoid impact on the audio band, I believe that the decision on the capacitor value can be done by ear (an excellent detector in the audio band).
Bridged amplifiers need special treatment. This needs two zobels, and each at "half strength," twice the resistor value with half the capacitor value--when two amplifiers are bridged, according to ST Thompson. Maybe I errored in the description? Anyway, the sum total of the two should be the same value as a normal single zobel. I have no documentation for parallel amplifiers.