How much should I rely on an external board or diagram when reading a chess book? I'm currently making my first serious attempt to read a chess book. While I can generally follow and evaluate variations mentally if I can at least see the starting position in some diagram, I struggle after the variations continue beyond the page and I can no longer see a diagram from which the variation departed.
I can copy the diagram on a board or simply on my computer (and do not move the pieces), but I wonder whether I should. On the one hand, being forced to remember and visualize the diagram trains my visualization skill. On the other hand, I catch myself flipping the page quite a few times and I wonder if this distraction is worth the trouble. I certainly don't intend to play blindfold, so I will always have some chess position in front of me when I need it, at least.
Now that I think about it, I'm not even sure whether it is good that I do not play the variations out on a board or computer diagram: I might miss things that the book doesn't want to spend time on, or spend too much effort on skills I should not be training. I have no clue, really.
How can I determine what would work for me here? Are there any texts out there that cover this issue? The book itself doesn't give much suggestions on how to read the variations beyond thinking on your own before reading the suggestions in the book, which I do.

This question is related, but I'm not really looking for what is common, I am looking how I can determine what is good for me, or what chess teachers believe is a didactically effective approach. (based on reasoning or experience)
I can copy the diagram on a board or simply on my computer (and do not
move the pieces), but I wonder whether I should.

It is very much worth while setting up a board and following the game on the board. But you should go beyond just passively playing out the moves on the board. You should stop after each move and actively consider what you would play next for each side. That will benefit you much more.
There is also the aspect of involving more of your 5 senses as I say in this answer to a different question.