Looking for sizing help w the y fliker. DS is turning 10 (about 52" and 75#)and DS2 is 7. I think it will be for the 10yo but prefer something they can both use, and maybe my 12yo DD (she's 5'4" although considering getting her own).

Any suggestions for model or the sizing? The 3 says for 7+ and the 5 for 9+, but thr 5 has pictures of teens using.