EILD and REM

I was thinking about the way EILD devices - like the REM Dreamer and Novawhatsit - are used to detect REM and send us a signal to make us realise we are dreaming. Does anyone know what happens when the EILD devices are used to improved recall - that is, they are used as an alarm to wake us when REM ends, rather than when it is in process? Obviously recall would be very good, with you having great recall for every dream in a night, but would this, in the long term, help one to have more lucids?

EDIT: Also, has anyone used these devices to interrupt a REM period - or several REM periods - as soon as they begin so that they will have a big REM rebound in the future?