Those links you posted are faulty.
Fuel flow capacity through such a filter is obtained from the "flow vs. ∆P" charting as found on the Racor Division - Parker
website. Look for your specific filter cartridge model number and its 'flow vs. ∆P" chart (where "∆P" = differential pressure/vacuum) - this chart is for CLEAN filters, not loaded with debris. The 'capacity chart will have both vacuum and pressure values. Essentially ALL filters are so rated and applied.
First you need to determine the theoretical Fuel Consumption of your engine at WOT (wide open throttle) from your engine manual, etc. .... then add 25+% to that value. Determine the MAXIMUM suction lift from your (new) lift pump in inches of mercury (Hg.) vacuum - this will be the suction pressure that the lift pump 'stalls' or can deliver NO flow as when a filter is completely 'choked' .... should be in the max. range of 5 or 6 inches of Hg. vacuum; such values are usually obtained from each engine's 'shop maintenance/rebuild manuals'.
The important thing is that you should be IMMEDIATELY changing out the filter(s) when the MAXIMUM lift pump value reaches ***75% of the maximum value of the lift pump*** as indicated on the vacuum gage. Example: (5" Hg. X .75)= 3.75" Hg. vacuum on the gage. as the rate of the debris deposition on the filter is 'exponential' because once a filter starts to become plugged it will begin to remove finer and finer, or smaller and smaller ĶM sized particles ... and the filter will then *very soon* 'choke' with these smaller particles AND the suction pressure of the lift pump will soon be 'overwhelmed' - all resulting quickly in NO FLOW.
When to change a filter as indicated on a vacuum gage
: at 75% of the value at which the lift pumps maximum 'draw value' (pump 'stalls') .... typically 5-6" hg. 'times' 75% = 3.75" to 4.5" hg. vacuum on the gage.
Vacuum motive filtration is Extremely inefficient: 1. because the lift pump cannot draw more than about 5-6" hg. vacuum. 2. the particles will be more or less IN the filter media rather than on the surface.
Boat builders prefer vacuum motive fuel filtration because its the cheapest and least labor intensive method to do the job (translation: cheap and dirty); plus, if you develop an air leak in the fuel system, the system rapidly and 'automatically' shuts down and doesnt fill the bilge (and surrounding water) with oil thus preventing serious EPA, etc. fines.
Commercial maritime fuel installations are usually PRESSURE motive fuel systems. Such Racors are usually designed for a maximum of 30 - 60 psig 'filter media burst pressure'. As you will see from the 'flow capacity curves' the higher the differential pressue across sthe filter - the higher the flow. Simply look at the specific fuel filters "flow vs. ∆P" curve and note that the 'flow capacity' at higher PRESSURE is vastly more in quantity (flow rate) than in vacuum motive flow .... It means that if you installed a 12 vdc PRESSURE pump on the tank or between the tank and the racors, the filter would have 10X - 20X the 'crud capacity', simply because its operating at a higher PRESSURE. Of course, the fuel delivery system now has to be 'bomb-proof' against leaks, cannot use cheapey 'compression fittings', etc. and should have 'double flared' stainless tubing instead of copper.
The 'compromise' is to install a 12vdc diesel compatible pump (automotive stuff) on the tank or between the thank and the racor, etc. filters so that when a filter is 'plugged' when run solely by the lift pump .... instead of shutting down the engine, changing a filter when underway, etc.; then, simply switch on the 12 vdc pressure pump .... and use the built-in capacity that is still available in the filter media when supplied by PRESSURE from the 12 vdc pump. BTW ... a 12 vdc pump so arranged will take out 99% of the 'bother' when 'bleeding' a fuel system. In this 'redundant' configuration the 12vdc is only ON when you need to 'bleed' or in an emergency (to get more FLOW out of a filter that became blocked while in 'vacuum' motive service) ..... thus enabling one to simply 'motor-on' for a short time until its SAFE to change out a plugging filter.