How do I prevent the camera from zooming in/out while I'm using the carousel?
Go into your control settings and unbind zooming from shift+mousewheel:

What is the difference between this and Quick Item Swap?
QIS uses a hardcoded table to determine which items to switch between, while this mod automatically generates the table by reading entity prototypes on map load. In other words, QIS only supports specific items, while this mod automatically works with all mods that correctly define their entities' upgrades. This mod also let's you customize / overwrite upgrade paths.

How do I define my own upgrade paths?
Go into the mod player settings page. There you will find a setting from CUC called Custom Upgrade Registry. This is a JSON table in the format of "entity-name": "entity-upgrade-name". For example, this table includes the power pole upgrades that come with the mod, as well as custom paths to switch between every kind of inserter that the base game has:

{"small-electric-pole": "medium-electric-pole", "medium-electric-pole": "big-electric-pole", "big-electric-pole": "substation", "burner-inserter": "inserter", "inserter": "long-handed-inserter", "long-handed-inserter": "fast-inserter", "fast-inserter": "filter-inserter", "filter-inserter": "stack-inserter", "stack-inserter": "stack-filter-inserter"}