I tried out your method, and it was a quite interesting. The position I took was from a Gazza game (as white):
I wrote down all the lines I could think of on a paper in the order I thought of them. My first 5 variations or so of analysis was quite horrible, but the more I calculated the more accurate it got. Some of my earlier variations I could replace with stronger variations.
After I finished the work (perhaps 30 minutes, didn't time it), I played out all the lines on the board and I managed to confirm that most of my analysis was correct, but one, where I actually gave a position a huge plus which was a huge minus =) However, I managed to find two main variations which lead to an advantage (1. a3 and 1. Qc2).
For my 1. a3 line I was able to to nail the first four moves, but in the 1. Qc2 I missed an ever better move on the 5th ply. I guess that means I can see 2-4 moves ahead with decent accuracy. On average, I looked three moves deep.
But I think the method has some flaws. I got to write down all my variations which really simplifies the task of memorizing it all. In a match situation I can't write anything down, I have to rely on my memory. I think this is also the problem, because I so often go "back and forth", while with the paper I don't have to do that. What I really need is a structured way of coming up with the variations and memorizing/categorizing/valuing them.
I did notice an interesting thing though: just enumerating all the tactical (and potentially tactical) variations first
seems to be a smart way of doing things because you then set out the constraints of the position. It took me 8 or 9 variations of calculation before I noticed I could even use the open diagonal to the black king. If I had first noticed this, I would have simplified my task alot (for those of you who have experience with AI, there is an analogy with partially ordered plans), however it is not that trivial to do, I guess.