The OS 32 is an ABC type engine which requires a different type of breaking in than a ringed engine.

ABC engines need lots of heat in the cylinder to operate properly.
Except on the first few runs when the piston needs to wear into the cylinder which is "breaking in". Running it "rich" helps keep the new and tight piston / cylinder assembly cool which causes it to wear rapidly which is what "breaking in" really is, RAPID WEARING of the engines internal parts.

The engines lower end does not need any sort of running in as the precision with which engines are made these days precludes it.

With an ABC engine you need to run it up to almost max RPMs with the needle set rich so it stutters in what is known as 4 cycling.. Do this once for about 3 min then shut it down and allow it to cool completely. This creates rapid wear of the piston / cylinder assembly. Now start it again but this time lean it out (needle turned in) so it alternates between 4 cycling and and 2 cycling. Run it for 5 min like this and again let it cool completely. Do this 5 times total and your engine can be flown at almost it's maximum. These runs continue "wearing" in the piston / cylinder but at a lesser rate.

The reason you want to heat and cool the engine a few times is this allows the alloys to expand and shrink and finally seat in place.

Ringed engines are a whole different ball game. They need the same heat cycling but must be run VERY rich for the first several runs.

An example of ringed engines would be the very popular Moki line.
A Moki 2.10 requires at least a gallon of fuel to run through it at a very rich setting in order to be broken in correctly.