I have a 57 fairlane & want to put spots on it.Is there a specific model for the year or are there multiple models that will fit?I have a chance to get a unity model H2-c I think it is.The entire unit is about 20" long.There are no mounting brackets with this are they available?Is there a template or instructions available for proper mounting?You only get 1 chance to drill a hole and would like it to be right.Any help appreciated! Thanks, Tom