Distinguishing stringent from relaxed?

[M.J. Pallen]

I am in the process of transduing a Tn10 relA mutation from one strain of 
Salmonella into another. Does anyone have a handy way of scoring the 
relA-negative phenotype, so that I can check that I really do have a relA 
mutation in the second strain? Cahel & Rudd in Neidhardt's E. coli & S. 
typhimurium book mention SMG medium. Is this the best way of 
distinguishing stringent from relaxed strains?