If you use it, I'd use a tiny bit (maybe 1 ounce per 5 gallon) and taste it daily until it has not quite enough and then rack it off of the oak. It's better to have too little rather than too much. You can't take it out once it's in there and it takes forever to mellow. Not a problem for a "good" wine, since you're aging it anyway, but the Welch's is more for drinking right away. I oaked my blackberry just a little tiny bit and after almost a year it's getting pretty good.
Mikey- No one's going to yell at you for giving your opinion- don't worry! I happen to love my Welch's wines, but others might hate them. That's ok. I don't like barleywines but it's the brewer's perogative to make them.