Pragmatically speaking, for battery health you should charge only as much as you need the battery, so it sounds to me that in your case that’s 90%. Also, here’s a paper about battery charging:
Strategies to limit degradation and maximize Li-ion battery service lifetime - critical review and guidance for stakeholders https://deepblue.lib.umich.edu/bitstream/handle/2027.42/154859/Woody_Maxwell_Thesis.pdf
The DMCA is a curse.