I also do this. A trick I've learned is to grab a PDF or Word or any editable copy of a document, then highlight sections with various pastel shades to indicated "don't care", "maybe care" or "get deep". Then on the second pass I can focus more intensely on the sections I need to get deep on.
Another trick I've learned is to find an older copy of a specification and read that first. Usually the older copies have less bulk, are more directly addressing the core conceptual issues, and are easier to read.
Sometimes if I want a rapid and superficial understanding I just go after the diffs or change notes for the last few versions of whatever it is. This can give a scattershot coverage of the contemporary state of the thing. It's not much but it's a place to start from.
Another trick I've learned is to find an older copy of a specification and read that first. Usually the older copies have less bulk, are more directly addressing the core conceptual issues, and are easier to read.
Sometimes if I want a rapid and superficial understanding I just go after the diffs or change notes for the last few versions of whatever it is. This can give a scattershot coverage of the contemporary state of the thing. It's not much but it's a place to start from.