The usual arrangement is a bailer either side of the centreboard casing, at the lowest point in the boat. I think the medium size one produced in stainless by Elvstrom/Andersen is the accepted choice.
To fit bailers in this position you will need to make a cutout in each floorboard so that you can get access to them.
Of course, there is an argument for not making two big holes in the bottom of a perfectly sound and watertight hull. If you are singlehanding in ‘fun’ conditions you will need bailers, but otherwise a pump can be very effective, assuming you have somebody aboard to work it.