I would suggest a wideband sensor with a display, most likely it won't pay for itself very quickly, but you would have some peace of mind.
The trick is to get your car to stay in open lope, maybe by disconecting an oxygen sensor. This may or may not work depending on the vehicle. Then, if your MAF reads in volts, you can just bleed voltage off the signal volt with a pot so the pcm believes it's getting less air than it actually is. Pretty simple, however my pcm doesn't seem to like being tricked
I have mine on a switch so I can go back to stoich at any time, so no need to up the idle.