Add a lot of yeast nutrient sold online or LHBS. Lack of nutrient will cause H2S gas and sulfur smell, because the yeast is stressed. Also, ferment it out of sunlight. A tablespoon of yeast and two tablespoons of nutrient will do up to 7 gallons. Make sure your starting PH is close to 5.2. If by chance it stalls along the way, add non-chlorinated water (half a gallon) and more nutrient. If that fails, re-pitch the yeast, yes, tomato paste (a couple of Tablespoons) will work, but it will discolor your wash unless you distill it. It will also really sweeten the taste of your product. I suggest inverting your sugar first with a little citric acid or cream if tarter to break your sugar down into simple sugars which are more easily fermented. As for making sugar beer, it isn’t tasty unless you add flavoring to it. 2 lbs of sugar per gallon of water is just about right. More than that makes it harder to ferment. SG 1.090 is the maximum of potential alcohol that is feasible. Stay away from Turbo Yeasts with sugar washes. It gives very rank flavors. Use a good ale yeast or DADY (Distiller’s Active Dry Yeast). Lots of people use Champagne yeast, but really, it is not the best, by far.
Oh, for beer strength 1.060 or 1.070 is a quite adequate specific gravity. 1.060 is probably best. Olive Nation sells great flavorings.