Thanks for joining in, and you bring up a good question and thought.
We have to briefly revisit the intent of all this - Paul's theory (if I may state it) is that there's too much oil for the oil control rings and bleed holes to accommodate, so KLRs burn oil when turning much over 5000rpm. All his work is focused on reducing the amount of oil going up under the piston. Early on, that was done by re-directing the oil to someplace (the transmission and cams) where it would do no harm and might be of some help.
More oil going to the cams is a good thing, but won't save the head of the engine runs out of oil. More oil sent to the transmission is a good thing and may help with the splash lubing of the upper balancer bearing.
Oil was redirected to the transmission and cams by removing the restrictions in the banjo bolts such that the bearing clearances became the control orifices, not the banjo bolts (edit: though, if I have it through my thick head yet, there is still some control at the transmission banjo bolt - only one orifice of .125")
A larger, straighter, oil line could further help with that by reducing turbulence, friction and so on, so let's take a look.
First, the inside diameter of the oil lines is .160". A banjo bolt with .125" cross drilling has a total cross section greater than the oil line.
The oil line is fed from the filter via the passageway and hole shown below:
The area of the .230" hole is .04"^2, while the area of the passage way (.115" x .235") is .03"^2. There's a corresponding passageway in the case that's probably the same, so the total cross-section of the passage way is .06"^2, which is larger than the .230" hole's area.
This is the mating passageway in the case:
I don't have a case to measure, but the matching oil passage looks like it is also .230" diameter. I'm also not able to confirm that the hole that mates to the .315" hole on the clutch cover is truly blind, but the oiling schematic doesn't show it going anywhere.
The banjos look like they could be made to accommodate a line that had a larger inside diameter; how large I don't know. 1/4" i.d. x 3/8" o.d. might be pushing it, but let's assume.
The banjo bolts have a M10 thread and a .160" diameter bore. To safely go to a larger bore would require going up to M12 banjos and (edit)
bolts and there is probably room to re-tap the ports to that size.
As a side note, I've installed a sensor in the test port bolt to get oil temperature. That bolt is also M10, and I tapped it M6 to accept the sensor. It makes me a bit nervous, as the difference between the M10 minor diameter and the M6 major diameter is just a millimeter. It will stay in there for testing, but I'm not sure if I'd trust it long-term. I think increasing the bore and cross drill on an M10 banjo might not be a good idea. Better to go bigger.
All in all, quite a bit of work would need to be done, but it is possible.