Politically correct answer : Follow the Owners Manual which says to keep below a certain RPM for the first 300 miles? Don't remember the RPM or mile off the top of my head.
Any Rotax Racing Engine builders have a preferred dyno break-in rpm/time preference you'd mind sharing ?
You can see dyno style routines if you search the web (This is what I usually do)..... found this one in an article on breaking in a BMW rebuild:
BMW motorcycle engine break-in
"...Install a new oil filter, using the starter (no fuel in carbs so engine will not start) to fill the oil canister area (OIL light goes OUT). Start the engine, using a minimal amount of 'choke', and within seconds move the rpm to about 3000 and hold it there for maybe 15 seconds, then move it upwards to maybe 3500 or even 4000... for perhaps a minute, I shut it off after that first minute, check for oil leaks, then I restart and IMMEDIATELY, no waiting, go for a ride. I DO NOT baby the engine...I use a fair amount of throttle. DO NOT, however, use over about 4500 rpm for the first dozen or so miles. Keep the engine around 3000-4500, as best you can, backing off the throttle fully every few blocks, then increasing throttle so the rpm is back in that range. As you get a couple of miles on the engine, you can use longer stretches without backing fully off the throttle (which 'sucks' oil into the top end). ... The idea is for oil to be sucked into the rings area when the throttle is OFF. It is OK to use a fair amount of throttle, but not wide-open throttle, and do not use extremely high rpm. After a few miles, you can move slightly higher in rpm. Don't idle the engine for long periods of time. After a fair amount of miles, stop, turn off the engine, and again check for oil leaks. If no leaks, continue your ride. I suggest finishing the initial break-in in the usual fashion as in such as the Rider's Manual...modest rpm, vary the rpm, vary the throttle, etc., and avoid very high rpm. After 50 miles or so, return home and change the oil to a quality 20W50 (or proper grade, depending on weather conditions for riding)...but do NOT use a synthetic until the engine is FULLY broken-in, which can take a few thousand miles sometimes. You probably will want to change the filter, and to inspect the pleating (disassemble the filter by prying the metal ends off the filter, then slit the outer wrap, then unroll and inspect all pleats. both sides). It's a good time to check the valve clearances after that 50 miles..."