Citi Signature vs Amex Platinum Edge for international purchases


I am just looking to see if I am missing something when using which card for international purchases.
I have both a Citi Signature Visa and Amex Platinum Edge accumulating points with the aim to transfer to KrisFlyer points.

For Citi I get 4pts/$ for international purchases and only 1pt/$ for the Amex. With the relative transfer rates for both to KrisFlyer (1:1 Amex, 1.5:1 Citi) I am better off using my Citi Visa for any international purchases (bonuses aside). Am I right?
Thanks guys

Given you know that your goal is to redeem for KrisFlyer miles - yes, you do have this right! Not much else to say, the earn rate for Citi Signature on overseas transactions is 3 KrisFlyer miles per dollar and Amex 1:1.
The forex surcharge should be roughly equivalent too. Worth testing that one day if you can.

Great, thanks Keith. Just wanted to be sure to make sure I am maximising my chances. Cheers.