Mr_Bill wrote:
The biggest problem (to me) is that
rats carry many diseases, most unpleasant,
some fatal.

Not only diseases !
My swimming pool heat pump stopped working a few weeks
ago and I discovered that rats had eaten half of the control
panel wiring harness- right through the metal wires.
I worked as an exterminator while I was in college and agree
with most of what you have recomended except that I have
much more respect for traps than you do.
Baited with attractive bait like half cooked bacon, I have
found traps to be best. Its essential to tie the bait down onto
the tongue/trigger. Set out a lot of traps and remove them all
after catching a few. Wait a week and reset in different locations
with different bait. Traps are messy though- nobody enjoys
disposing of rat corpses.