I've only seen one good SC 'issue' type frock; currently no one is offering such a thing but I'd be happy to share info with anyone interested. Anyway, about any domestic wool/cotton mix is acceptable but I'd stay away from wool/hemp as there's zero evidence that this was used in SC. I have numerous copies of bills submitted by the early war contractors in Charleston. One of the favorite textiles was the "Salem jeans" from the Fries (Sp?) Mills in SC.
Eagle buttons are a good choice followed by SC, then civilian and lastly wooden in that order.
Hope this helps.