Others may chime in with recipes of which they have personal knowledge. Have never tried sweet potatoe or the more regular type of spud for wine but probably like most, can recall hearing of someone who'd made it and 'swore' by it.
Couple of sites for recipes you could try are Jack Keller and Honey Creek. Jack has both types of potatoe listed. His site is favoured for pretty well anything pertaining to home winemaking, deservedly so. Honey Creek's not too bad either, FWIW.