Menu#4a has a link to general info for a MAF (MAF Troubleshooting and Testing) along with typical voltage output levels. As you surmised, the amount of air flow is turned into a voltage; the more voltage = more air.
As far as interchanging MAFs from 119 and 104, it is "theoretically" possible if you could design a ckt to translate the output of one (119) to be equal to the other. Practically, it's not possible.
Well when you amass all that info you can teach us . . . .
PS: the other day, I checked my Lambda to see what's what; oscillating between 48 to 56 at idle and the same at 2K. Seems like the 'cleaning' is still 'effective'. I sold the K&N filters and now using paper!