Botts played in the days before sudden death time controls.
You should, if prepared, play a line of stuff without too much thinking until you get to an unfamiliar spot, when you need to start looking and calculating. Old rules of time management are pretty obsolete.
I've been having alot of trouble managing my time in slow games: I simply play to slowly. After a bit of research, I stumbled upon this notion of "Botvinnik's Rule" which states that in "normal" openings (the ambiguity of that notion aside) you should spend rougly 20% of your time on the first 15 moves.
Of course this is a guideline or principle like any other, and the complexity of the position should dictatehow long you spend on a given move. But such benchmarks are useful to indicate "more or less" whether you're spending too long or too short on thinking.
Is this formulation helpful? What other benchmarks do people use? To help, at the outset, calculate more or less where they should be at what stage of the game? (I'm talking slow games here!)