I saw a thread here https://forums.gta5-mods.com/topic/9360/map-editing/25 and the last two people were asking about deleting occlusions. This is not necessarily a tutorial, but it should help people wanting to mess around with deleting occlusions to get started. You can see that I successfully deleted the occlusion in CodeWalker for the one building, but I did not test it in game to see what the results are.