Current Transfomer (CT) ratio setting on energy meter
A CT steps down current and a CT specified as stepping down in the ratio 50:5 is the same as stepping down current in the ratio 10:1 so, if you put 10 amps through the primary, you get 1000 mA into your burden resistor (you haven't mentioned this so I assume you know what you are doing or have bought a CT with one inbuilt).

If you put two primary loops through the CT's hole then, in effect you are doubling the ampere turns and if you put 10 amps in you will get 2 A out.

I have no idea what the smart energy meter requires you to enter as values so I can't help you on that one.


  I believe I have to set primary CT ratio to 50 and secondary CT ratio
  to 5.


That's just plain old-fashioned mumbo-jumbo. The primary doesn't have a ratio and neither does the secondary - the primary-in-relation-to-the-secondary is the only thing that has a ratio: -



In the picture above, the primary is 1 (1 wire passing through the hole) and the secondary looks like 10. This means 10 amps in produces 1 amp out (just like your CT).


  Now, if I have two rounds of the same 120 volt wire passing through
  the same CT, then I would set secondary ratio to 100.


Get a grip of this - there is no such concept as a primary ratio (unless there are two primaries and I've never heard of that for a CT).