This is magus's post on the gentleman, it explains how to do this pretty well
"f you don't hit anything you should also do the hold A method, but you do need to slow down the timing a bit to make up for not having the added hitlag. Holding A (or Z which also acts as an A input) on the 3rd hit until after you IASA out of the jab sequence will always be beneficial since rapid punches are triggered by comparing your total A input duration vs total time. The reason holding the 3rd input helps is because each A input duration is only determined on release, so if you never actually release the 3rd A input and IASA while still holding it that 3rd one doesn't get included in the total at all.
Gentlemans are made easier by keeping your total A input duration low (releasing the A button faster when doing the 1st and 2nd punches and holding the 3rd input to omit it), and your total time high (spacing one or more of the punches farther apart and hitting something which adds hitlag to the total time). As the total A input becomes shorter and/or more hitlag is added, the time between punches can be shorter while still getting the gentleman. When the total A input becomes longer and/or less or no hitlag is added you will need to space the punches out more."[/quote]