First, forget about the procedures. Focus on what people DO and how much of it there is.
A process is a “bucket” to collect those activities. And then you must measure each bucket. If you have 100 processes, you have to measure 100 things. If you only have 6 processes, that’s easier. But it depends on the size and scale of your company. Most companies never have more than 15 top-level processes defined, so that should give you some scale.
If you have a single bucket (like “production”) that has a lot of sub-parts to it, decide if you want to measure those sub-parts independently. If so, break up the process. If not, keep it all together.
When you’re finally done, you can assign the procedures (documents) to the applicable processes. Some processes might have 1 or 2 procedures (possibly even 0) and others might have 100. That’s OK.