How often to tack... Angle to destination

[KiwiKen]

Firstly determine which tack is the more advantageous, that is the one to take, but how far you move to port or starboard from the rhumb line is a matter of judgement.

Long tacks can put one at a disadvantage if the wind direction changes.
However, where tide or current are a factor, then generally the favoured tactic is to lee low the tide or current, because the flow is moving you to windward, and one would then would probably tack on a tide change to maintain that benefit.

[jmschmidt]

Do you keep a DR plot? 100 degrees off the bow or 10 abaft the beam to an imaginary point to weather from the first plot, assuming no or little wind shifts.