The Following is a Jack Keller Recipe that is probably pretty close for your grapes:
"MUSTANG GRAPE WINE (Sweet, Red) 
10 lbs. (one gallon) black Mustang Grapes
2-1/4 lbs. granulated sugar
1/2 gallon water
1 tsp. pectic enzyme
Champagne or Montrachet wine yeast and nutrient
This wine may have too strong a "wild" flavor for some. It can be blended with almost any thin wine without detracting from the flavor. Remove the stems and wash the grapes. Place in large pot with one cup of water and set over low to medium heat, covered. Stir with wooden paddle every 10 minutes until grapes break apart and juice oozes out. Allow to cool. Meanwhile, boil water and pour into crock over sugar, stirring to dissolve. Set half of sugar-water aside in quart jar. When grapes are tepid, over crock pour grape juice and pulp into nylon jelly bag, tie bag and leave it crock with juice. Add yeast nutrient and pectic enzyme. Cover and set aside 10-12 hours. Add yeast and re-cover crock. Use wooden paddle to push bag under juice twice daily for 7 days. Drain bag and press pulp well to extract residual juice. Measure acidity of liquor, then follow one of the methods below to reduce the acidity to 7 parts per thousand (p.p.t.) tartaric if necessary. Pour into secondary fermentation vessel, top up with reserved sugar-water, fit airlock, and let stand three weeks. Rack and top up with remaining sugar-water, then rack again in three additional weeks. Set aside two more months. Rack and allow to clear. Wait one month. If lees are still being deposited, allow another month. Stabilize at 1.000 to 1.008, allow 10 days for all yeast to precipitate out, rack, and bottle when clarity returns. May taste immediately but improves remarkedly with age. [Author's recipe.]"
You can't go wrong with a jack keller recipe so have at it and let us know how it goes. My only suggestion is to freeze the grapes first. Then put in the pot with a cup of water to heat as in the directions above. That will just help with the grapes breaking apart and releasing the juices.