Hey Nathan ,
how are you doing :-)
See, I have tried that long time ago and it didnt work quite well just adding more CPU and Memory to the VM, oin fact I wouldn't do it in real production environment.
The thing is Large deployments creates machine with 8 CPU's and 8 GB RAM whereas Medium with 2 CPU's and 6 GB RAM.
One good solution would be adding more VCS's into the existing cluster.
Is the current CPU / Memory utilization high?
Regards//Andrey