i know this is a long thread, but i would encourage trying to read all of it.
lat9 incorporated my changes into version 2.4.0, which is the latest version available for download on the plugins.
please confirm you are running that version and still having problems without corrections.
with regards to the confirm order button click, there already is a spinning gif. it is located here:
includes/templates/template_default/images/confirmation_one_loading.gif
do you not have that file? does it not show up when one clicks confirm order?
that spinning gif is also easily replaceable by any of the numerous ones available on the internet. an internet search such as these returns results:
https://tinyurl.com/y57y5pd6
https://uxplanet.org/using-loading-a...e-cab0097be9f1
downloading this one, renaming it, and putting it in the right place will certainly have your customers talking (MO):
https://i.pinimg.com/originals/83/2f...2caeaa6145.gif
best.