but i guess sleeping uses some memory and other stuff,
that i could use for Mac Partition......?
No it won't use any memory (RAM), if you suspend Windows using VMWare Fusion, as you close Fusion. It just writes the suspend state to the file Fusion uses for storing the Windows OS.
Suspending lets you continue in Windows where you left it.
If you are worried about speed during starting Windows, you could time both methods (suspend and shut off, which means you have to boot Windows again, if you want to access it) and see which is faster.
I always use suspend, and experience no memory lag after I close Fusion.