The RKC snatch test has gone through a few evolutions over the years. Originally RKC candidates were allowed one hand switch, depending upon the candidates' weight they had a specific number of reps to complete with NO time limit.http://www.dragondoor.com/certification_14.html
Then the Snatch test changed to one snatch for every Kg of body weight with a max of 100 reps, a 5min time limit was imposed but multiple hand switches was allowed. One could even set the bell down and have a smoke as long as they hit their required reps in 5 min.
For myself and for most of the people I train grip seems to be the big factor in putting up solid snatch numbers. So lets start by taking grip out of the equation. I am a big fan of the SAID principle (Specific Adaptation to Imposed Demand) in training. If you want to increase your grip strength for snatching the 24kg then snatch the 24Kg.