A model working is attached, you are free to modify to suit your requirement. In the absence of clear cut HR policy I could only imagine certain general allw./pattern which may or may not be in line with your thinking. Before proceeding further you should refer to the Terms & conditions of apptt.of this employee and take care what has been committed therein is not omitted in finalising this structure. Most of the components have no legal backing or stipulation and therefore consent of both the sides are enough.
The model of Rs.5 L p.m. is anyhow outside the purview of compulsory deduction of EPF act being > Rs.15k salary. And again 12% itself cannot be part of earnings being a deduction towards EPF. In order to itemize the components such a high income this has been deliberately accounted in 'earnings' , therefore 10 or 12% doesn't make difference as it's voluntary variables. Employer is free to have their own quantum & different heads of components such as Refresher allow, incentives, festival gifts, business devt. allw., sumptous allw, chauffeur/chowkidhar allw, Lawn & furniture/Quarters allw. and so on.
The CTC structure depend upon the compliance level and scale of salary payable to the employees.
In case all employees are of low scale than a simple CTC format can be applicable for all. However, if higher salary scale also than it should be Tax friendly and maximum take home nature.
Pls find attached standard format (ESI Included and excluded).
You can modify the structure as per your requirement and company policy.