Your thought process is definately on the right path; however, I'm going to breakdown your question into pieces.
What you would like to do
1. Set up a field in the Customer table called CustomerWebsite
2. Need to be able to edit this field in:
- New Leads
- Edit Leads
- New Customer
- Edit Customer
3. When a lead is converted to a customer, retain the website information.
A few comments based on your requests, since the website will be tied directly to the lead / customer you do not need to do anything with the Contacts table (which is great because it means less work!).
Leads information is actually stored in the Customer table; however, they are distinguished from Customers in MethodCRM by a field called IsLeadStatusOnly.
For more information you can follow up here:
add the website information to leads / customersHow to
1. Create a field in your customer table (looks like you have already done this)
2. Create copies of the afforementioned screens (New Leads, Edit Leads, New Customer, Edit Customer)
3. Once you create these custom screens, you will be able to see the new field CustomerWebsite on the left hand side (Insert Fields and Object Menu).
4. Drag and drop that field into your desired location on all 4 screens.
5. Start converting your leads into customers and all of that website information should be retained in your customer screens.