"The client cache on Windows computers stores temporary files used to install applications and programs. Choose Yes to specify Maximum cache size (megabytes or percentage of disk). If this option is No, the default size is 5,120 MB."
After some testing I got the answer :) When applied to a client the Maximum client cache size will be set to the smaller value.
For instance when
Maximum client cache size (MB) = 5120 MB
Maximum cache size (percentage of disk) = 90%
and the disk size of the client is 100 GB, the maximum cache size will be set to 5120MB
On the other hand when
Maximum client cache size (MB) = 5120 MB
Maximum cache size (percentage of disk) = 2%
and the disk size of the client is 100 GB, the maximum cache size will be set to 2GB