I showed up without a reservation, and got lucky. A couple was there with a kid, so one of them had to stay back and I took the place. That said, there is access to the store and paid tasting even if one is not on the tour. I would suggest showing up as early as you can and then go to the shop the first thing, so you can get access to the meager daily quota of restocking. I didn't and therefore could find nothing worthwhile to buy. The 3000Y price is true... a great bargain! Had the time of my life and a very pleasant walk back to the train station (however, be careful: I fell asleep on the train and almost missed getting off at Shin Osaka on my return).

The other option I did not know about then is that you can order liquor on Amazon Japan. If you have confirmed your hotel, then you can order with an appropriate lead time and have the hotel hold shipment for you. This is what I am going to try on my next visit!
Cheers.