Nice work! 
I've just noticed that you're already using the new dialog for multiple search criteria. With v2.99b I've changed the delimiter at SearchBy to be two pipe symbols || (see this topic for discussion).
This means, that the SearchBy field for your tag source would now be
[SearchBy]=Country||||%s||Language||||&lang=%s||Query||[$if2([$meta(CollectionID)],$if2(%albumartist%,%artist%)[ %album%])]||&term=%s
I also invite you to create a dedicated topic for this web source at #development:web-sources-scripts so that others can find it more easily.