Failing to study master games

Quite some time ago I've decided that my chess training should combine 4 elements:
- tactics
- endgames
- practical play (CC, OTB, live)
- all the rest
"All the rest" was planned as study of master games mainly. And here I fail regularly. The problem is that due to constraints of family life and work I do chess in chunks of 15-30 minutes. That's enough to solve few tactical exercises, study 1-2 endgames, play a rapid live game or make few moves in CC. But that's never enough to go through a master game even once.

So I will either go through a game and comments very fast, then it's rather shallow and I feel like learning nothing. Otherwise I have to split it into several chunks where I do nothing else but only study this particular game because I need like 2-3 hours to really understand one game in depth. And I never succeed in this - I'd start one game and then it's dragging and I forget what was going on, loose focus and eventually drop it.

I've discovered recently that positional exercises can be a nice alternative. You find them in books like "Can You Be a Positional Chess Genius" by Dunnington, "The Chess Cafe Puzzle Book 2" by Muller or "Test Your Positional Play" by Bellin and Ponzetto.
Here you are usually presented with one critical position from master game. You have to analyze positional factors, make a plan and implement it. Playing it against a computer is quite interesting too. One exercise can be completed in 15-20 minutes which fits well into my time constraints.

I will appreciate your comments and ideas.

youtube offers quite a few annotated master games. not too time consuming. learning value may be questionable, though

best advice i think is solving endgame studies(without moving the pieces around on an analysis board) and doing the same for tactics problems(the sort you get where it's mate in 3 or win decisive material). these will improve your calculation skills. second best advice is study the opening you like in great depth, spend time on each opening move starting at move 1! of course before you do this its important to have a basic knowledge of the endgame and opening rules. hope this is useful, it helps me.

sorry i should say because of your limited study time, try 15 - 20 minutes of what i mentioned, and at the end of the session write down your ideas so that you can continue when you're ready, otherwise if you're like me you forget your ideas. that way if you dont solve a problem or find a good move in the opening after 20 minutes you can come back to it with some notes to carry on.