If I was to get a virus in an M$ OS which was running in VMware- could/would it be able to infect my main machines M$ OS or would it be contained/confined in the files of the VMware's OS ?
NO Thats the whole point of Vmware. Vmware basically puts a Virtual Hard Drive in your computer and installs the OS on it. It acts as a seperate hdd and CANNOT infect your main pc.
I plan to also test different AV solutions in VMware run OS's and therefore your answer is exactly what I needed to hear 
now THAT's BUSY