It's not really any more demanding to rate 150~ Pokémon than it is to listen to anywhere from 40 to 70 songs like we do in music rates. It doesn't take 3 minutes on average to rate a Pokémon; a quick glance and a number between 1 and 10 is all the effort it takes. Provide a link to a page like this
http://pokemondb.net/pokedex/game/firered-leafgreen and have people run through it quickly. This website in particular has a dex like this for every gen, as well as a complete 649 national dex.
I can't imagine it would take more than 30 consecutive minutes to finish one generation, probably less. The MAIN issue will be the countdown. The hosts can't reveal the rankings one at a time.
Oh, and I don't know if you guys are running generations simultaneously or if you're doing them one by one, but don't do them simultaneously. If you bombard people with a bunch of rates to do at once they won't do a single one of them.