VMware ESXi VM allocation

Hi, with below hardware spec Windows SBS 2011 VM is allocated according to below details- planning to add more Memory - what would be ideal memory for this. Is this server capable of running 1 more VM as terminal server windows 2008?

Physical server Description: HP ML350p G8
6 CPU x 1.99GHz
Xeon CPU-2620 @ 2.00GHz
Processor Sockets :1
Cores per socket:6
Logical Processors: 12
Memory: 16GB
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Windows SBS 2011 VM allocation:
Memory: 14GB
No. of virtual sockets: 4
No. of cores per socket: 2
Total no. of cores (CPUs): 8

Thanks