Turns out the MPS2315 isnt available on JLC assembly, so I have to choose a new buck converter. Chose this TPS54302 Buck converter from TI and the documentation for it was really really good. Turns out the schematic for this also has less parts and has the added bonus of zero (or very little) dropout (dropout is the minimum input voltage to still output 5V). The buck will still be able to provide 5V/3A as a BEC - not bad. Used a 22uF input capacitor and 2x 22uF output capacitors. The input pin “EN” lets me set a UVLO (under voltage lock out), where the chip will turn off if the input goes below a certain voltage (EN takes input from a voltage divider). The chip has internal weak resistors for EN, so the standard UVLO is ~4.4V, which is perfect, which is why I left EN as no connect.