But I think we can make it work. Cork swells when it gets wet. So only tighten the bolts enough to get a reasonably snug fit--that WILL leak. Then flush that toilet every couple of hours for a day or two so that the leak will wet the cork, causing it to swell up and seal the connection.

I learned that trick from my engine mechanics when I bought a 20 year old project boat. A pair of Chrysler 318s that hadn't been started for at least 5 years. When the guys got 'em running again, the rear main bearing seals leaked like we were pouring oil through 'em. Replacing the seals would have required pulling the engines, at a cost of nearly $5k. But I had wonderful mechanics...they told me those seals were cork and cork swells, so let's just put pans under the the engines and keep putting the oil back in and see what happens. 3 weeks later both engines stopped losing oil completely and never lost another drop in the 6 years I owned the boat.

So if that worked for a couple of engines, it oughta work for your toilet. If it doesn't, buy some rubber gaskets.