News re my plan as above:
Well, I finally got to do it. Had to wait till I had 950 miles on the oil. After cooling off a bit after a 20 minute drive in the CRV last weekend, I tried to insert a plastic tubing (same diameter as my dipstick's width) into the dipstick tube but it wouldn't go in fully, couldn't reach the oil level. So I tried a smaller, 5 mm diameter plastic tubing and it went in deep and now reached the oil level. Connected the tubing to my large trap bottle and pumped away. Man, it was a slow process. Took 2 hours, with some timeouts to keep the pump from getting too hot. I got almost all of the 3.5 liters of oil out.
To filter it, I bought a small orange plastic cone, the type you put on the road as warning devices, but this one's only a foot tall. I drilled a 1/4" hole in the small end. Turned it upside down, and inserted a sink trap filter with wire mesh, as far down as it will go. This left me a 3" tall area to put in my filter medium, which consisted of 8 layers of tissue paper similar to that used to dry our hands in the washroom. I made it hug the shape of the space in the wide end of the cone and trimmed off the excess. Now I had a hat-shaped filter. I really wanted 10 0r 12 layers, but thought it might be too thick and impede the oil flow too much.
The Shell Helix 10W-50 oil started out new with a yellow color but now is a pink color. I can pour only half a cup of oil at a time into my makeshift filter, and it takes 3 hours to work its way through that tissue paper, LOL! I've gone through only 25% of the 3.5 liters of oil till today. But the car is not in use yet, so I have all week to get it done.
To make matters interesting, I've actually looked at the oil with a medical microscope at 400X magnification. The first specimen was fresh out of the engine. Most particulates were half a micron or so, and they looked like small dots to me. The rest (about 1/4 percent on my estimate) were about 1-3 microns. These were black and irregularly shaped, and I just assumed they were soot particles.
The next specimen was taken from the now filtered oil a few hours after I'd started the filtration. All particles were somewhat less and fewer than the first specimen. There were very little that remained of the 1-3 micron particles.
I took a third specimen today, after I thought some more of the "pores" of my filter would have become smaller owing to having trapped more particulates. Sure enough, there were fewer particles scattered about the microscope's field of view, and there were no particles bigger than 1/2 micron!
Just some other observations: The oil fresh from my engine and the filtered oil have the same exact shade of pink. In other words, perceived color did not change even after the oil went through my "external bypass TP" filter. And the other observation is my oil smells of the E10 gasoline I'd been adding to my tank at each fillup with pure nonE10 premium gas. I'd drained 28 liters of this 2-year old E10 from my VW Beetle a year ago before I sold it, and I'd been feeding it to my car 3/4 of a liter at a time for the past 11 months. I still have 4 liters to go before it's all used up.
When all the oil's been filtered, I will take a 4th specimen and report on what I'll see.