Depends on your preferences.
Think about when you drive down the road and see a fence... If the top is
level, do you notice it? Or, if the top is parallel to the ground,, do you
notice that?
Whatever you think looks better... After all... It is your fence.

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remove one of the @'s unless you are a spammer.
"RB" wrote in message
...
I'm going to have to replace a 30' section of privacy fence. The ground
under the fence is uneven and is lower in the middle than on the ends.

Is it easier to put a string across the top, and cut each board to length,
or simply put boards up following the ground line, and then make one long
cut across the tops to level them?

Also, what do you do when you get to a point where a standard width board
is too wide for a fit? Rip it the whole length?