1) Pick a bank that gives expiration dates within 3 years. 60 => 36 combinations
2) Security codes are always 3 digits. I don't know why you think 4? 9999 => 999 combinations.
2) Security codes are always 3 digits. I don't know why you think 4? 9999 => 999 combinations.
However, it's easy to tell the difference between an AMEX and a VISA/MC from the card number alone.
The 4 digit code on the front is their CID, asked for by most merchants.
Some discussion, which doesn't shed a whole lot of light though: https://insideflyer.com/forums/threads/what-is-the-3-digit-c...
I don't recall ever being asked for the three-digit code on the back (like I am with most VISA/MasterCard credit cards). It's always the four-digit one on the front.