Such report shall contain the following:
(a)
Plans and specifications which shall set out, among other things, the general type of street lighting system in each zone. The lighting systems to be improved shall be divided into zones and in each zone shall be grouped those systems of approximately the same general type. It shall be sufficient description of the location of the lights to be improved if such plans or specifications show or describe the approximate location of the lights.
(b)
An estimate of the cost of the improvement, for the period of time during which it is proposed to be continued.
(c)
A diagram showing the proposed assessment district and also the boundaries and dimensions of the respective lots or parcels of land within the district, each of which lots or parcels shall be given a separate number upon the diagram. The diagram shall govern for all details as to the extent of the proposed assessment district.
(d)
A proposed assessment of the total amount of the costs and expenses of the proposed improvement upon the several lots or parcels of land in the assessment district in proportion to the estimated benefits to be received by such lots or parcels, respectively, from said improvement. If any portion or percentage of the costs and expenses of such proposed improvement is ordered to be paid out of the city treasury, the amount of such portion or percentage shall first be deducted from the total estimated cost and expense of such improvement, and the assessment proposed in the report shall include only the remainder of the estimated costs and expenses. The proposed assessment shall refer to such lots or parcels upon the diagram by the respective numbers thereon.