OS recomends 18% lube and 5-15% nitro for all there engines 2 and 4stroke the 1% is negledgable a little extra oil is not too bad for a 4st up to 20% is fine,heli fuel, 4st fuel,airplane fuel, there all basicly the same.
as long as there within the specs of the engine your running there fine for use fuel is labeled for marketing.
the basic components are the same, alcohol, nitro, and lube.
it wouldn't hurt to add a couple of oz. of oil to the fuel at 17% theres about 22 oz of oil in a gal of the Omega a couple more wouldnt hurt.

the engine your breaking in was set up for 15% nitro and 20% lube its the base levels for OS engines running less oil you should run it a little rich is all for the break in runs.