Throttle position

What’s throttle position you use in MAF scaling, WOT or just gently speed up?

You need to vary the throttle position and engine RPM to reach all the areas of the MAF table. So gently changing the throttle (to avoid transient conditons), and holding it steady is the best way to generate data allowing to you determine the correct MAF translation.

As David said, you need to start of gently to allow the scaling to be corrected progressively, with the engine under low stress - if going straight to WOT with it a little out it could cost you the engine.