Greg,
In my opinion, today's movies (and concerts) on Blu Ray are produced with at least a 5.1 setup in mind. And that includes at least one Sub. A 5.0 channel system will at best be somewhat of a compromise.
I think you need to look at the Bass management & downmix capabilities of your receiver. Dolby TrueHD reproduces audio bit-for-bit identical to the studio master. So if the Studio Master has low frequency portions sent to the Left & Right, Center & Surround speakers, it is available to your receiver to produce. With regards to the LFE signal, I've never thought about it. I checked some of my manuals can't find any way to direct those signals elsewhere.
However, my Denon manual advises if no Sub is selected then the Fronts (Left & Right) are automatically set to "Large" which means full range with no routing of the bass. You have the option to set the Center & Surround speaker. I caution you, that although many speaker OEMs state their speakers are rated to very low values (say 30 or even 20 Hz.) they rarely provide the volume output at these frequencies or accurate graphs displaying same.
Please advise the models of the potential Cerwin Vega speakers and your receiver and the folks here can provide good guidance.
