Current ILSAC PCMO service category in the grade specified. They don't have higher approval than ILSAC AFAIK. Not saying this is adequate - but that's where they are. Previous Toyota internal memos announced any current API/ILSAC PCMO in the preferred grade as a "Genuine Toyota Motor Oil".
I'm sure either of those choices will work wonderfully in your car. I don't think that MSS is any more like TGMO compared to most other off the shelf 0W20s (opposed to other car manufacturer's house blends (TGMO, MGMO, HGMO)).