Slow feeding a fermentation

I want to try my hand at making a stronger wine.
1. Can I slow feed my fermentation with welches concentrate right out of the container without worrying about contamination?

2. If I want to slow feed my fermentation should I not add camden tablets until I am done slow feeding?

3. After primary fermentation I was gonna rack into a secondary with a can or two of the concentrate and continue to do this until It wont ferment anymore.

4. I was gonna start with a high alcohol yeast what ever the home brew shop recommends so when I rack to secondary should I add additional yeast?

Thanks!

1. I would assume the contents of an unopened container are sanitary. The rest is up to your sanitary practices.
2. Campden tablets will kill the yeast in the wine. You can add them before you begin fermentation and wait a day before adding the yeast; you should not add them again until all fermentation and feeding has ceased. And by then, frankly, it should be quite unnecessary.
3. I wouldn't bother with a secondary until fermentation stops; then you could just use one as a clarifying tank. Racking is more work, a contamination and oxygenation risk, and will pull the wine off of much of the yeast.
4. See above. You could, but i'd be a waste. Just leave it on the original yeast until fermentation is done.