There is no limit to the size of drive you can use with the DMS tools.
At present the last tested drive stands at 250GB only because no-one has tried anything bigger.
When buying a drive the recommendation is stick to 5400RPM drives.
I'd also wait for v2.12 of the tools (not far off now) to save wasting space, as 2.10 is wasting a bit of space on new DMS'.