To set points ignition timing accurately, you will need a meter to measure the dwell angle (amount of rotation in degrees the points are closed for), and a strobe light to check the timing marks line up at specified engine speed.
On bikes which have had all the ignition parts replaced with new there is no real need for a dwell meter, but on those using original ignition parts, wear will mean its very difficult to set points accurately using feeler gauges.
Before setting the timing up, the condition of the points needs to be considered, and if they are burnt or worn should be replaced, ideally changing the condensors at the same time.
Next thing is to check the dwell angle using a meter, and adjusting to the specified figure, and finally checking the firing point using a strobe light at the RPM specified by the manufacturer.