I don't know the maximum of translation slots available when PAT is used

1) PAT uses the high ports for translations; therefore the available translation slots per IP are calculated via 65536-1024 = 64512.

2) Almost unlimited as a hash value is used to identify the translation instead of using the TCP port. The hash value is calculated using the source port and IP address as well as destination port and IP address, this will allow to have more that 65000 connection with one IP.