flywheel horse and rear wheel

That will be hard because the dynos are all individually calibrated. When I was involved in a chassis dyno shop we used 18% for automatic, 15% for manual cars. IN most cases this was backed up by owner provided info but you never knew if the engine dyno was happy or sad... The places using higher figures may believe they are right, and the engine dyno being compared to is off - any they may be right, or full of crap... I tend to think chassis dynos when calibrated right are more "real", because they include all the power limiting factors that engine dynos don't. The intent of engine dynos is usually to safely break in a new engine, and provide a number for the owner or bragging rights for the shop or owner.
That's why the informed enthusiast will say it's a tool and the numbers are guides only, not gospel.