Well, the only tip I really have for getting any jump into a tuck, from experience doing it myself and coaching my teams with it is to do whichever jump then just bound up as if you were going to tuck. Just like a roundoff boundup, just do the jump and bound up just to make sure you have to technique of doing a jump into tumbling, until you get that down and comfortable with it then start trying it with the tuck. This is how I got myself used to making sure that I am keep my head up and throwing my weight up instead of throwing everything back. And another tip, get someone spot you!!