Attempt at automatic rebalancing for LND with rebalance-lnd, although it could fit any script... 🤷‍♂️

auto_rebalance.conf

420183667455285923,rompert.comguy,20,20
590034546445293500,otherpeeralias,20,20

auto_rebalance.sh

#!/usr/bin/env bash

#####
# Attempt at automatic rebalancing for LND with rebalance-lnd, although it could 
# fit any script... 🤷‍♂️ The config file can't contain comments, format is 
# <channel id>,<some label>,<trigger if funds on local side are less than N%>,<trigger if funds on remote side are less than N%> 
# The script will order the rebalancing to stop if it's still going after 600 seconds 
# and kill if it's not stopped 30 seconds after that. Oh, and spaces in the config breaks stuff.
#####

REBALANCE="/path/to/rebalance.py"
DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
SOFT_TIMEOUT=600
KILL_TIMEOUT=30

cd $DIR

for line in $(cat ${DIR}/auto_rebalance.conf)
do
        channel_id=$(echo $line|cut -d, -f1)
        peer_alias=$(echo $line|cut -d, -f2)
        local_threshold=$(echo $line|cut -d, -f3)
        remote_threshold=$(echo $line|cut -d, -f4)

        echo "⚖️  Checking ${peer_alias} (${channel_id}), will rebalance if less than ${local_threshold}% of funds are on the local side or less than ${remote_threshold}% are on the remote side."

        if $REBALANCE -l -r "$local_threshold" -i |grep "$channel_id" &>/dev/null; then
                echo "🤖 Moving funds to ${peer_alias}.."
                timeout -v -k $KILL_TIMEOUT $SOFT_TIMEOUT $REBALANCE -t "$channel_id"
        fi

        if $REBALANCE -l -r "$remote_threshold" -o |grep "$channel_id" &>/dev/null; then
                echo "🤖 Moving funds from ${peer_alias}.."
                timeout -v -k $KILL_TIMEOUT $SOFT_TIMEOUT $REBALANCE -f "$channel_id"
        fi
done

I suggest to use --econ-fee, the default fee configuration most likely isn't successful. I also don't think rebalancing to 50/50 is the best idea, maybe just send 100k sats (repeatedly) until you've meet your threshold?