Have you considered using Item metadata instead of tags? See Design Pattern: Using Item Metadata as an Alternative to Several DPs for an example. It gives you a much better way to associated this sort of information with an Item and will free you from needing to build the dictionary, you just need to query for the values. It would also be more language independent (i.e. the same Items would work with a JavaScript version of the Rules).
Have you given any thought to supporting Strings instead or in addition to Numbers? The amount of processing or CPU difference between them is almost unmeasurable in this context but with Strings you can use meaningful names instead of needing to remember that 1 means Foo and 2 means Bar and so on. You can use mappings with a String Item just like you can with a Number Item.