Just came across this thread today! Normally I just open up reflector-simple every so often (maybe like 1-2 times a month?) to update the mirrorlist. If I can set it and forget it with reflector-auto, then I’m all for trying that out. Now I haven’t done anything explicitly yet since I would like to make sure what I’m doing is verified by someone else first before I go ahead and save everything. On my system I already have reflector and reflector-simplepackages installed. I’ve used the following command:
sudo nano /etc/xdg/reflector/reflector.conf
and my edited file looks like the following below. Note, I am in the US, so if anyone can just make sure I did this all correctly, I’ll go ahead and save it and then run sudo systemctl enable --now reflector.timer to allow this to run each week so I don’t have to worry or think about it anymore 
GNU nano 5.8 /etc/xdg/reflector/reflector.conf
#
# See "reflector --help" for details.
# Recommended Options
# Set the output path where the mirrorlist will be saved (--save).
--save /etc/pacman.d/mirrorlist
# Select the transfer protocol (--protocol).
--protocol https
# Select the country (--country).
# Consult the list of available countries with "reflector --list-countries" and
# select the countries nearest to you or the ones that you trust. For example:
--country US
# Use only the most recently synchronized mirrors (--latest).
--latest 10 (default was 5, I changed it to 10, but should it be 20 maybe?--this message will be deleted before I save this file, fyi--)
# Sort the mirrors by synchronization time (--sort).
--sort age
Basically I just want to do what reflector-simple does, but automatically. The comment above me @blahnik added a few other values, i.e. sort rate, age 4, completion-percent 100, score 30, and I’m wondering also if I should or need to include any of those? Any additional help or pointing me in the right direction would be most appreciated, thank you!
Edit: Side note, I know this topic is from last year, so I don’t know at all if it still applies and is relevant now or if maybe I should just ignore it all, please let me know, thanks.