Yes, that's right, 160mm rotors. Too small? You think I should go with 180mm? 😂 Remember, the larger the rotor, the better the heat dissipation and the longer they last.
Again and again and again, like a broken record over the years, there are only two (2) Shimano RD that you need to know for 10-spd, 1x on small wheels. You and I have been through this already, and it's been covered extensively on the channel.
For 20" wheels, the RD is the medium-cage
Shimano Deore RD-M6000-GS part which though rated for 42T max cog can span a 46T cog no problems and which several YT vids show can safely span 50T. For 11-speed, there's also the
Shimano XT RD-M8000-GS and the
Shimano SLX RD-M7000-GS parts.
For 16" wheels, the RD is the short-cage
Shimano Zee RD-M640-SS part which though rated for 36T max cog has been shown to be able to span safely and competently a 42T max cog. All of my tours, domestic and international, since 2016 have been with this RD, and it is still working great on my
FnHon Gust 16", having provided admirable service on three other bikes across three countries. Scraped, faded, but none the worse for the wear, it continues to shift crisply and accurately to this day after eight years of continuous service. This is the no-brainer you want, though at $60 apiece it ain't cheap. Buy once, buy right.