Cobbadog- I can assure you, that through both my personal experience in paint spraying, as well the (admittedly advertised) testimonies written on the Frantz website, the toilet paper filter is superior to ANY other attempt I've tried.
When spraying high-gloss black paint on a vehicle, even the most minute particle can be seen. The smallest fiber will show up, as it's got the surface tension to break the continuum of the paint film. At no time have any of the fibers of the toilet paper roll found their way onto any paint I've sprayed. Nor have other foreign objects found their way into my paint. Thus, I must find that "bulky stuff" and fine stuff IS successfully filtered through toilet paper.
Likewise, please bear in mind that once a standard oil filter "clogs" and the spring-check valve is opened due to excessive pressure to the oil filter, ALL oil goes into the by-pass circuit, and up into your engine. Unfiltered oil. This Frantz filter uses no bypass valve. All oil that enters its system is filtered.
Obviously, any filtering that does occur with the Frantz filter is done so through the paper element chosen by the end user. Thus, IF one were to use a poor choice, or a mis-fitting paper element, the filtering characteristics would be inferior to a superior choice.
In general, the Frantz concept is used in concert with a primary oil filter. BUT, one CAN use an adapter to cause the Frantz filter to be used as a primary filter element.
One more point: ANY filtering of oil in a Listeroid engine is superior to NO filtering of oil in a Listeroid engine.