Need to sync the carbs on my 84 Venture. A friend of mine says he can sync them using 4 seperate vacuum guages http://www.canadiantire.ca/AST/browse/4/Auto/AutoTools/MultiTesters/PRD~0251039P/Pro%2BVacuum-Pressure%2BTester.jsp (haven't bought them yet). This is more convenient then a Carbtune since I can find them locally. My question is how accurate will this be compared to carbtune or syncpro?