No with variationTypes I meant you keep the same source per entity, as it is implemented in Obstacle.qml in Squaby.
Do you really need different appearances for one variationType, or could you reuse the same entity with different variationType settings?
You are right, loading of the sprites of a spritesheets takes longer than images, because the file information of the json file from TexturePacker nneds to be extracted and the sprites are more complex to create. You can alleviate the problem by pre-creating entities at the application launch or when loading the level first time and showing a loading screen so the users don’t get impatient. Pleas also see Squaby how we implemented it.
The runtime performance of sprites is much better than with images, because only a single draw call is involved and not one per image! The number of required draw calls is one of the most limiting performance factor on mobile devices, so you should get a decent 60fps up to a couple of hundred images. If you want to test the performance differences of Images and sprites you can build the PerformanceTestCollectionMain.qml file in the examples folder of the V-Play SDK.
The build server will support z-ordering with the next release 😉