I myself would stay away from grape tannin in a pineapple wine, I'd think that combined with the acid from the fruit it would just be too much, my pineapple wine, which I've done a few times and revised a few more, looks like this:
for a 1-gallon recipe:
12-16 oz water (spring water works great, as long as it's pre-boiled)
1.5 cups Sugar (I used Evaporated Cane Sugar)
Fill with 100% Pineapple Juice (Trader Joes brand, stay away from cans if possible)
Lalvin 71B-1122 (metabolizes some of the malic acid, this yeast is important)
Pectic enzyme/nutrient as directed on package.
Ferment for 3 weeks then rack onto 1/4 of a fresh pineapple, cubed. Leave on fruit for 10 days, then rack again. Ready at 6 months, but just gets better with age.
It goes over very well with anyone who likes pineapple or spicy white wines, reminds me a bit of a dry reisling, pairs great with meditranian cooking.
Primary:Russian River Redemption clone, Kelly's Melomel, Graham's English Cider 22-23
Aging:Public House Dry Stout, Procrastination Porter, Mr. Brown Ale, Westvleteren 12 Clone, Mead, Duvel Clone, Graham's English Cider 6-21, Belgian Draak Strong Ale, Fig Melomel, Acerglyn, Restorative Tonic Metheglyn