There's not really a "black or white" answer, but I will go ahead and throw out a figure of around 3% to 6% of remodeling budget.

What if it's a very simple design, not taking the design professional very long or requiring much work, but high-end or exclusive products were chosen, which sent the remodel costs to $220K? Or, what about the opposite? What if the designer spent months on the project, but their client went cheap and bought low-end product and the job came in at $80K?

There are just too many variables for a simple answer.

Hello Graf Development,
Thank you for your quick response, it was very helpful.
Bill T.