You can also use different number ranges for the Repeat statements, for example one sheet symbol can have `Repeat(Test,1,10)` and the other can have `Repeat(Test,11,20)`.
I don't think that it's necessary to disable 'allow sheet entries to name nets' because of the bus connection, and within each sheet the net names should get resolved with suffixes by default to avoid duplicates, but it depends on the overall set of options you have selected. There are a lot of different ways to set up net naming, and several of them will probably work.
In some cases it's easier to throw in an intermediate sheet that wraps a subsheet and marshals all of the nets out in a way that works better in the top level schematic. Or you can just place individual sheet symbols in an intermediate sheet and then optionally repeat that intermediate sheet. Lots of options depending on how many channels and what the project is like. As long as the source sheet is the same across all instances you should still be able to use all of the normal multi-channel PCB features across all of the lowest-level sheet instances (although sometimes the channel classes get screwed up and you have to fix them manually in the Project Options window).