I have been drafting and designing for design-build firms for the last 5 years. I'm used to the client signing a design retainer with a deposit for the design services, and then any time overages being made up for with margins on materials and labor during construction. I am now striking out on my own to design and draw plans as my own company for other contractors. I would seriously appreciate any feedback on how you more experienced freelancers structure your rates. Do you apply an hourly rate to drafting work that is already designed and a flat rate (like a design retainer) to work that you're designing as well? What else do you typically sell to your clients? Do they buy materials and cabinets through you, the designer, and leave the contractor to mark up the labor and rough materials? Any reading material you can recommend on the subject would also be greatly appreciated.
Just a young designer/draftsman looking for some advice from the abundance of experience we have here. Thank you, everyone!