Low level aeros are very specialised and for display purposes are covered by the DA system with all sorts of controls. (Good old EASA have rejected the UK DA system as it was invented here and saves lives
) The actual techniques are modified to increase safety margins because low level you don't have many options. The comment above about completing the maneover then adjusting the exit for effect (with light pull) is an example.
Barrell Rolls have a bad history and are not flown in the classical way to make them safer without spoiling the look too much.
Brian used to do a Roll On Take On at 30 feet (didn't like it so much in the Extra as he could see where he was going
). He managed to display for 25 years professionally so it can be done with the right focus.
DA pilots must have practiced their display 3 times before every display (and sign to say so) but have mentally rehersed many times more.
Not something to be entertained without a lot of training, supervision and compliance with the associated rules.