Had my alternator spin tested at an automotive electric specialty shop, he said the alternator tested great under all parameters. The shop stated allot of people come in with specific specs they want confirmed. My question is what exactly are the specs I should be looking for. 

With engine at idle and operating temperature, with all lights and accessories turned off, measure AC voltage between the alternator's B+ terminal (that's the big stud with the red wire attached to it on the back of the alternator) and the negative battery post.  The voltage should be ≤ 0.03.