Not sure you will be able to "fine tune" it enough.
Most earlier years can run without MAF sensor connected, but they run in Safe mode/Limp mode.
See if your model will start and run without MAF plugged in
Each computer has software for the engine size it is running, so it knows the air flow based on RPM and throttle position, without MAF sensor data
Air/fuel mix is WEIGHT based
14.7/1 is the ratio used for air/gasoline engines
So 14.7 POUNDS of air to 1 POUND of gasoline
14.7grams of air to 1 gram of gasoline
(this is why pre-vaporizers are hooey, lol, volume doesn't matter, WEIGHT matters, just FYI)
Fords MAF sensor is a heated wire, heavier air(sea level) cools it more than lighter air, colder air cools it more than warmer air.
Heavier and colder air has more oxygen so computer needs to add more fuel to stay at 14.7/1
So MAF sensors main function is to tell computer the WEIGHT of the air coming into the engine so it can adjust fuel WEIGHT added accordingly.
There is an IAT(intake air temp) sensor also used.
If computer adds too much fuel you get a flooded engine
Not enough fuel you get pinging/knocking and damaged engine
So pretty important to get the WEIGHTS right
On a carb you could manually adjust the ratio, and get it wrong often, lol, not "good ol' days".
Computer fuel injection is better, in oh so many ways, but it does require the correct information to do the correct calculations, just like carb needed correct adjustment to do correct fuel mix.
You want to modify the air flow into the engine, which is fine but you also need to give computer the correct info for that air WEIGHT.
Not sure you can with 5.0l MAF/housing, but never tried
Found this page:
http://www.rogueperformance.com/ModifiedMAF.html
Never tried this modification but it has a line I found interesting
Note: This is just the MAF BODY. Ford used 3-6 different calibrations on their MAF's each year,
so a complete replacement is not practical.
So not sure you will get where you want to go with the 5.0l housing