nishimark: thanks again for the advice - namba sounds great - if the vibe's anything like shinjuku it will be just my thing.

fumitani: spot-on, i'll be singer slinging the way back

valve bouncer: thanks, and will definitely think about your suggested itinerary.

just discovered that the whale shark is in another facility and will only be back in kaiyukan end-august. i'd probably still visit the aquarium anyway, though the attraction's somewhat diminished.
this leaves me open to considering other ways of filling in the time before the flight - i could linger in kyoto, but osaka would be such a different experience that i'd rather spend the bulk of what little time i have there. too bad dotombori appears to become livelier the later it gets, when i'd already be at the airport.