This one seems to be a success except for my handling of it once it was finished. The yeast smell is way in the background, and with a whopping SIX tablespoons of vanilla flavoring it had better be. I used one half cup of sugar for the yeast, and the Splenda equivalent of a cup of sugar for sweetness. Jay said it seemed about right. I think this indicates just how much people (at least in the U.S.?) have gotten used to a lot of sweetness and a lot of flavoring.
My mistake was siphoning the soda from the chilled bottle into another. The intent was to have a bottle that could be treated as any other soda bottle, without having to extra careful to avoid stirring up the settled yeast. The result was a tremendous loss of carbonation, so the very final result wasn't the ideal. This has me pondering complicating things by seeing if I can set up one bottle with sugar and yeast to generate the CO2 and pressure and have another bottle be the actual soda mix. This would allow me to leave sugar and yeast out of the final soda completely, at the price of a more complex arrangement. Whatever I do, it won't be for a while. I don't want to start another bottle (or whatever) until the current batch is gone. That might be a while, as neither Jay nor I drink very much of it since it has sugar in it.
Meanwhile another 1 L bottle of anise soda is going. I started it the same time I started #5 of the cream soda, but with the last of the first packet of champagne yeast, which wasn't very much. So I'm letting it go for a rather longer time in hopes of getting more carbonation by simply waiting longer. It appears to be working, but I won't know for sure for a couple more days.