Difficult acelerometer calibration

So lets say I have a large drone that makes the Accelerometer calibration, either due to size or weight.I read the article about calibration in the wiki, and the only thing it says it is to calibrate the board outside the drone.

This method seems to carry a few risk, it will be difficult to replicate the position of the board inside the drone when its outside.

Am I worrying too much or my doubts are justified? Is there a trick or something?

Perform the complete calibration off the drone and then after installation perform Calibrate Level (single axis).

I have not seen an impact on flight performance. Neither on a large Hexacopter (sky-hero Spyder-6) nor on a small copter