I'm not Granger, but I like Obbligato ;>D
I think Obbligatos and Auricaps are similar in that they both bring out 'detail'. I think both are caps you can't go wrong with using.
For ref.>>>squeezebox(apple lossless format)>FP III w/ OB 2.2uf(non-extended...yet)> Parabee w/ Auri coupling and OB parafeed caps...JJ 300b> Klipsch Hersey II w/ Auri's in crossover. Except for the cap changes, everything else stock.
With the 3.3uf Solens, the sound was nice and out in front of the speaker.
With the 10uf OBs, the sound stage became deeper, more bass(cut back on my subs in Sexy speaker arrangement), more detail.
The parafeed cap is between the plate/choke and OPT. I also returned the bottom of the OPT to the cathode(hum pot center terminal) instead of grd.