How is your ear to the tune of 5 grand? Run it rich like you mentioned and you shouldn't have a problem. As long as it is good 'n rich it would probably be OK even at 7K+.
Use the recommended prop for break-in and run it close to WOT (wide open throttle) using your high speed needle to tone DOWN the RPM. If you have some extra castor oil on hand, add a little to your first few tanks. Say 1/2-3/4oz to 16oz of fuel. It is a good idea to pre lube the whole engine with oil (10-30 is fine) especially the valve train. Takes a long time for the lube to get there under normal conditions. Remove your rocker cover and oil up things in there and inject some into the crank breather also. You can leave it off if you like for break-in just make sure you replace it the correct way when the time comes. Some fella's take the rear cover off before any of this and rinse out anything that may have been left from machining? I use kerosene for this and it is a good idea to do it. You don't want to use a solvent base cleaner as it will eat up the o-rings. 99% of the people don't do this, so the choice is your's?

I run the engine for about 5 min. Shut it down and let it cool. Repeat that for the first tank. Second tank run it dry. Third tank I start to lean things out a bit at WOT using the high speed and giving it brief high RPM settings. You can usually tell if things are still too tight?
I Broke-in many of 4 c's without a tach and never had a problem. Pre lube and don't overheat by running it lean and you will be fine. Good Luck.

Happy Fly'n....