EDIT: Thanks to MR. O.G. of the TSI forums mr. Ryan Mills, I have found his measurements for the AWE spacers and the diameter of their "flow holes".
LINK TO O2 SPACERS
This is the cliff's notes from seeing his pics:
Pre-cat sensor: 1/2" diameter flow hole, length of total spacer is 2" including threads, 1.5" spacer body not including threads
Post-cat sensor: 1/4" diameter flow hole, length of total spacer is 1 5/8" including threads, 1.18" spacer body not including threads
Now, our next experiment if Kaban wants to measure his UNUSED spacer jet on the RAI, is what is the diameter of the middle jet? If it's 1/2", and the smaller one is 1/4", we may be on to something yet again. I will email RAI and see if they can measure their long spacer as well for length and the diameters of the flow holes on the inserts.