It's funny how some people form such a strong opinion about an oil they have never used.
I don't use any oil, my wife might use a bit of KY now and then but thats it AFAIK.
I know enough about engines to know the engine doesn't give a rats rear about a little thinner, a little thicker or a little higher VI or any other such things.
I form my opinion based on 42 years of tearing engines apart and seeing the wear and tear first hand.
My father being the owner of a machine shop most of my life taught me to use micrometer and other measuring tools competently. I know the difference between wear you can see and wear you can measure and what it means.
If the engine is built for and specs for xw20 then it should wear okay regardless what brand or VI as long as it meet the spec.
I routinely run 5w30 and 0w40 in Honda 0w20 US spec engines and after 100K see no additional wear on the cams, cranks or cylinder walls. In the case of the iVTEC 3.5 i see less.
I ran a Honda 4 banger on 10w60 for 12 years and over quarter of a million Km and there was no wear outside of factory new spec. I had the engine apart to change an internal stretched chain. It was spec for 10w30.
Going thinner than spec can be risky while going a little thicker can bring better results in many engines like the VQ35De engine. In any case there is no risk going slightly thicker if you live outside the arctic circle.
The OP has a Honda not a Toyota why would he want to run the thinner Toyota oil?
Maybe Honda doesn't care what 0w20 you use.
The may be a small mileage hit from a light 20 to a heavy 30 but between a 0w20 and a another 0w20 its not going to be noticeable and it isn't going to make any difference to the engine whatsoever.
There is nothing magical or special about TGMO, nothing at all. Its just a light 0w20 oil nothing more and nothing less.
I am not bashing the oil, its a good oil but it is not any better than Mobil 1, PP, PU and a host of others in any way. The engine will likely outlive the body on any of them when the oil is changed at regular intervals which IMHO is even more important than what brand of oil you choose.
Change the oil at the proper interval and the engine will say thanks for that and keep on running happily.