For the driving ability of most of us on here, no, there is not going to be a discernable difference in unloading the t-bars and making things ideal. However, if you are a person who can feel the difference a half a tank of gas makes in the turn in characteristics of your car, then yes, you probably should make every effort to make things square, level, and blueprint ideal.
I’m definitely not, I get caught up over details more than anything. It is more a case of ‘while I’m there’ as it wouldn’t be a chore to do so. I will be checking square and level as best as I can but I am confident it won’t be perfect.