Ok the esteemed @IllThinkAboutIt and myself are working on a new Arizona/Utah location guide
https://www.spaghetti-western.net/index.php/Utah_and_Arizona_locations
It is still very much under construction, and we will draw from all kinds of location hunting knowledge all over the net.
Please do help out, we can use tips, directions, pictures (both from there as well as the appropriate pictures/screenshots from specific scenes in the films)