I've got the small clarke blast cabinet, which supposedly requires 10cfm at 80-100psi, however my 3hp cheapo keeps up with it reasonably well.
Constant blasting does mean the compressor never stops, so I do stop occasionally to give it a rest, but it's not caused any issues so far.

I suspect a Hydrovane 5 might be a bit on the small size, however you could always couple it into your existing compressor, and run them side by side.