I did some poking around and found a heavy body blueberry recipe by Jack Keller. Think I"ll use that as a starting point with adjustments made for using juice. Recipe follows:
• 2 32 oz jars of Knudsen 100% blueberry juice
• 11 1/2-oz can frozen red grape concentrate
• 1/2 c light dry malt
• granulated sugar to s.g. 1.090
• 1/2 tsp pectic enzyme
• 3/4 tsp acid blend
• water to make total liquid 1 gal
• 1/2 tsp potassium sorbate
• 1/2 tsp yeast energizer
• 1 tsp yeast nutrient
• wine yeast
Mix all ingredients except potassium sorbate, yeast and red grape concentrate. Stir well to dissolve sugar, cover well, and set aside for 12 hours. Add yeast, cover, stir ingredients daily. When specific gravity is 1.030 siphon liquor off sediments into glass secondary. Add red grape concentrate (do not top up), fit airlock and set aside. Rack in five weeks and again in two months. When wine is clear and stable, rack again, add potassium sorbate and a finely crushed Campden tablet. The wine should be sweetened some to pull it off dryness. This simply brings out the flavor of the blueberry. Set aside a final 30 days and carefully rack into bottles. Allow a year to mature.
I can do this batch of blueberry and still have enough left over to do a blueberry/pomegranate combo. Think I'll try to tackle the blueberry first and then set my sights on the combination. Still not sure what to do about the tart cherry juice. I've read that some folks mix it with the black cherry to get something wonderful.