I see no one has replied on this - I think a fairly small amount will do at that level, since here is what the manufacturer's website says:
Superfood® is a complete yeast nutrient. By stimulating yeast growth and survival, it can significantly reduce stuck fermentations. Research reveals that the best yeast food is not a single nitrogen source, but a combination of ingredients. Superfood® contains yeast hulls, yeast extracts, vitamins, and minerals.
The yeast hulls provide sterols and survival factors and adsorb toxic fatty acids, particularly decanoic acid, which tend to inhibit yeast growth. Diammonium phosphate is a basic nitrogen source and helps prevent Hydrogen Sulfide production.
Superfood® is not implicated in urethane (ethyl carbamate) formation. Yeast extracts contain amino acids, making them a rich food source, and vitamins and minerals, which are essential to vigorous yeast growth. Together these ingredients create an excellent, balanced nutrient for yeast.
Superfood® is recommended for both grape and non-grape musts, cider and beer. It is especially useful for musts that have a history of sluggish fermentation or Hydrogen Sulfide production. Superfood® is most effective in preventing stuck fermentations when added with yeast inoculation. It may also be added once fermentation starts to help prevent Hydrogen Sulfide formation. Superfood® is certified Kosher, except Passover.
Usage & Storage:
4-8 lb per 1000 gallons of must. Nutrient deficient must may benefit from the addition of extra diammonium phosphate. To help restart a stuck fermentation, add 1 lb per 1000 gallons when the wine is reinoculated with fresh yeast. This product is hygroscopic and should be stored cool and dry.
So your measurement sounds sufficient at first glance. I don't think it will harm the starter to be a bit high or low. It is mainly yeast that has autolyzed and DAP, with probably some zinc.