How to Approach Studying

OK, I'll admit it...I don't have all the answers.

One of the issues that I find myself bumping up against is how to study.  More specifically how to  structure my study time.

i.e. let's say that I need to work on openings and endgames (hey, I do!) and I am using The Sicilian Taimanov: Move by Move and The Russian Endgame Handbook (hey, I am!) to study.  If I have two hours of study time on a given day I can't figure out if it makes more sense to study each subject for an hour or choose one and dedicate the entire two hours to it.

I've tried both and I'm not sure that one is more effective than the other, etc.

My issue is that right now I need what I feel to be extreme amounts of work on both my openings and my endings.  I don't want to set one aside to work on the other, but I'm almost to the point where that seems to make the most sense.  i.e. I'd study nothing but openings for several weeks followed by studying nothing but endings for several weeks.

I'm wondering if anyone has any input based on their own experience.

Please let me know your rating when you reply.  I don't think that a higher rated players opinion automatically makes them more qualified than a lower rated player  For example, would you rather listen to someone who's gone from 1000-1600 in two years or someone who's gone from 1800-1950 over ten years?  Instead, I am curious as to whether there is a "rating bias" towards one form or another.  I don't think that there will be though.

Thoughts?