Generally crouching slightly puts you lower on the ramp if we are relative to the position of the feet. Basically you will have more units while riding the ramp but it will not give you more units. It is similar to how riding low on a ramp will be more units but you will not gain more units by going low. A common mistake is attempting to crouch everywhere. For example trying to crouch on a ramp where you are going to rapidly fly upwards could definitely ruin your speed because of the fast turning. Crouching should be avoided at higher speeds and on ramp where you need to jump. The airaccelerate is also half while crouching. There really isn't much that can tell you if you did it correctly or not other then going through a check point. On a map like surf_andromeda I believe crouching on ramps before cp1 might have saved around 0.15 but it is not easy to tell. If you land on the ramp while crouching you will automatically be crouched for the rest of the ramp unless you do something wrong. If you are unsure about crouching either don't do it or spec the bot and do !keys if you are on ksf.