In one of Carroll Smith's books...either "Prepare To Win" or "Engineer To Win", he stated that he sets his race engines at 300rpm greater than peak HP. If you use this rule of thumb, yours would be 5900 (6000 sounds fine). Any higher than that and you are losing efficency and perhaps being harder on components that needed.
There is also a neat site online which you can find the mathematically BEST shift points from an acceleration standpoint. Use you dyno sheet and transmission gearing in the following online calculator.
Calculating Optimum Shift Points
hope this info is useful
Andy