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I tend to use the subcategories/categories for the standalone "hub" pages on a topic, rather than the tag pages. And I agree that it's important to not have too many uses/not enough uses of a tag, which is really where the need for standardization comes into play.

In general, I would avoid promising any specific number of links at all. With the clients expecting this number each month, it can lead to teams building lower quality links just to meet their quota and fulfill the promise to the client. It would probably be wise to tweak the language you use and possibly re-think how you're tiering out that service. I'd recommend to group out different types of link building and tier it based on the complexity of the strategy.

I'd also recommend checking out Rand's final presentation from the 2016 MozCon; he gives some good directional advice on how to approach Link Building and some solid strategies and tactics to consider:

https://seomoz.box.com/shared/static/2462nsyjoeifyxaaivllh6541dz8zrwh.pdf

I hope this helps!