I have created this wonderful, amazing tool to help you see what the smallest (or largest) increase in project value or decrease in costs can have on your overall profit and margin.
Simply enter Your Desired Margin, Rates (hourly, daily etc) the amount of time and their relevant cost (hourly, daily etc, to match). You can then hit the 'Run What If? Scenarios' button and see what affect changes will have on your profit and margin. (Clicking or tabbing out of fields will update the figures)
If you need help with anything below, more than 10 resources, delving further into things, why not get in touch with me on LinkedIn.