Good idea Eth, I just tossed the 1.5L MAF on and went for boot.
I did have a co-driver and he did seem to come to the same conclusions on the same things as I did.
So I put the 1.5L MAF inside the airbox - note their are 2 type of 1.5L MAF's that I have run across, by this I mean that they have one tube runner still blocked but they have different air bypass holes around the outer circle (the two side by side are all the same between 1.5 SOHC, 1.6L DOHC, 1.8L SOHC). The MAF I picked was the one with the largest of the bypass holes opened up or not blocked off totally as the case may be.
The car was tuned after a good highway run to warm up the oil for a good 20 mins. I tuned at 10 PM at night because you can hear so much more with so little energy in the air.
Idle was good and stabilized without hesitation and throttle response was good as lots of air was seen by the sensor versus being bypassed by one of the two large runners being opened on the 1.8L MAF I had just used. I noticed that the timing which was still set at 9 degrees ACTUAL was allowing the motor to rev almost "effortlessly" into the 4000 RPM+ range but the power was smooth and not very powerful but the engine seemed subdued although likely to be at home revving in that area as the power was seemingly dialled back. I meant "effortlessly" because you didn't hit the 3000 hump that seems to mark the performance felt from the exhaust and timing catching up in the proper range; thus there seemed to be less power present but it did feel reassuring and didn't sound wrong at all (no ping at all setup this way!).
Next was to dial the timing to 9 degrees BASE timing and see what happens. The engine was a little peppier in that you seemed to get more torque from the timing bump but I could get ping in the same range that is always plagued with it on low octane pump gas between 2200 and 3500 rpm, things seem to sound a little better after that (you can still make out ping even with my muffler setup).
Onto 7 degrees BASE timing, and that yielded decent power but no ping for the most part. I still think my power experienced was reminiscent of the engine before mods to anything and especially the TB which in this case was the only reason the engine tips in from idle and helps clutch engagement so well. I know that I should now be looking at opening up things on the 1.5L MAF because it seems to be the most friendly for use with the 1.8L ECU and combo. I may try what Eth mentioned about the little black stoppers or even bigger still
and see what ping or not ping or timing I can dial in. This seems to be worst part of the swap because although people have done it, nobody has written alot about what they have experienced beyond a couple sentences and having run high octane fuel. Don't get me wrong, those that have been running it for a long time are not the ones I would appear to be angry at, I just want to find out for myself what works on the intended budget of low octane fuel, base motor a couple easily sourced DSM parts and a little ingenuity.
I will update some more after letting the ECU settle in for few days and see what the 1.5L MAF does at cold idle with 15W40 in the pan; I think my idle will get raised tomorrow morning.
P.S.
All the MAF sensors so far will not seemingly trip a CEL on any ECU (1.5L,1.8L) I have used so it would appear that the MAF element is universal at least from the 1.5L SOHC/4G15, 1.6L DOHC/4G61, and the 1.8L SOHC/4G37.