Hmmmm - the old question rears its head.
The only safe time to bottle your wine is when there's not a single cell of yeast left in it. That applies whether it's (apparently) dry or has residual sugar left in it. Any remaining yeast can (and probably will) start a referment which will produce carbon dioxide and therefore pressurise the bottle and run the risk of explosions.
So, how can you be sure?
The easiest and safest way is to allow any wine to ferment out to complete dryness and then store the wine in bulk (rack it - repeatedly- to get it off the deposit and then store it in a demijohn or larger container, with minimal airspace above it and under an airlock. If it goes through a complete cycle of seasons (that's a year) without restarting, you're probably safe to bottle.
If you want to retain some sweetness (although the best idea is to add sugar much later when you're sure you've de-yeasted successfully), then you're into the game of stopping the fermentation with the use of metabisulphite (and, if you want to be really sure, sorbate).
I've noticed that so many people want to rush to the bottling stage. What for? Wine matures better and more quickly in bulk, and the older it gets without throwing an extra deposit, the more sure you can be that all the yeast has gone. The time to bottle is when you can say to yourself "Yes, I'm going to start drinking that in three months' time". There's no great advantage in keeping wine in bottles for much longer than that (and I don't care how good it is).
So, back to your question - when is it time to bottle? When you haven't seen so much as a hint of a bubble for months, when the wine is star bright and has no deposit, when a hot season has been gone through with no yeast resurrection AND when you're beginning to think about drinking it. If you can't meet those criteria, decant it straight out of the demijohn and enjoy it (but remember that you'll have to get rid of the whole gallon within a week or so - what a trial!!!!)
Mike