What does that Hughes cam require for pressures? If you have the typical ".600 lift" springs liek with most aftermarket head assemblies, they are not enough spring for that cam. Lift means very little in determining a springs ability to control the valve with a specific cam. Pressures are what you want to look at.
And yes, if it's flat tappet, never break in the cam with the inner springs installed. This is true for any dual spring assembly. A single spring with the flat wound dampener is NOT a dual spring.