Making In Store Comparisons

[yyyiiikes]

When you go into a store to compare displays, how do you ensure the comparison is fair? I mean suppose someone has jacked up the settings on one TV and you were comparing it to the other. Would a good approach be to hit factory resets on both TVs for a baseline?

Also, is it fair to compare one manufacturer in a 46" to another in a 40"? Obviously one would like all things to be equal but sometimes that is the way the TVs are placed at the local stores.

Thanks.