b) Set the width units of lines to pixels. Points are not good when the render is made 96 dpi and points are 1/72.
.75pt = 1 pixel

You can also enter a pixel amount, e.g. 1pix (it must be keyed in with no space)

When you press Enter to apply the change the amount in the Width text entry box will show .75pt.

You can enter any pixel amount in the same manner.

The Help menu contains a list of abbreviations for all the other measurements.

Hope this answers one of your questions :-)

Gary