Pipe Chanter Pitch
To make your overall chanter sound sharper take a little hemp off the bottom of the reed and place the reed deeper in the reed seat.
To make the overall chanter sound flatter put a little more hemp on the bottom of the reed and lift it out of the reed seat a bit.
Making a small change in the reed height makes a big difference in the pitch so make small changes. Also, the changes you makes will have a greater effect on the high hand notes than the bottom hand notes.