For measuring bearings, you may do better not to draw the line. The Jeppesen folding nav plotter and the ASA CP-R plotter both have lines printed on them which you can line up with your end points. These lines will be straighter than anything you draw! The idea is you slide the line along the track till the protractor bit can be lined up with a True North line. The CP-R plotter has a grid of North lines which make this easier.
It is a very personal choice, though - choose whatever works best for you.
For the calculations, do as much as you can with a calculator, it is much more accurate than the Whizz Wheel.
And good luck!