I would start with the glow plugs,and worry about the timing afterwords if it is still a problem.Light gray smoke is normal when using ether.The easiest way to test the glow plugs is with a test light,and all you have to do is place the ground clamp of the test light on a positive battery terminal,then remove the glow plug connectors and touch the test light to the glow plug,if they are good it will light up.To test if you are getting power to the glow plugs,remove all glow plug connectors and place the test light ground clamp on a negative battery terminal,then touch the test light to the inner part of the connector while the glow plugs are cycling,and it should light up if all is well.
Rock