High gravity as a substitute for high speed relatistic time dilation effect 

From the article:

Using time dilation under the Theory of General Relativity, for instance: 
Residing inside of a hollow, high-mass object; 

Are you sure this is accurate?  I was under the impression that according to the shell theorem, the net gravity inside a hollow, symmetrical sphere was zero.  If the hollow object isn't symmetrical, there could be some gravity inside, but in that case it would be no different from (and probably less efficient than) standing on the outside of a high-mass object.