Hello, beginner adult gymnast here - posted about my roundoff for advice sometime ago and it is slowly improving 
Different question today: so far I have been mostly doing floor and, more recently, vault. Those are there to stay, but eventually
I would like to learn something in 4 out of the 6 men apparatus (in UK at least amateur competitions at higher levels require 4 apparatus).
Any advice on which one to choose? I don't feel particularly interested in pommel horse, but feel free to try and convince me.
A few criteria which may help: learning gymnastics is hard so I would like the two apparatus to have similarity so that learning one helps with the other (or with floor/vault but that seems less likely). I am 170cm for about 63 kg, pretty good shoulder mobility (for a standard adult, not an elite gymnast!). I have played a bit with rings and high bar, never tried parallel bars. I feel like I would like to learn high bar the most, but perhaps parallel bars and rings have more similarities?
Thanks in advance!

Different question today: so far I have been mostly doing floor and, more recently, vault. Those are there to stay, but eventually
I would like to learn something in 4 out of the 6 men apparatus (in UK at least amateur competitions at higher levels require 4 apparatus).
Any advice on which one to choose? I don't feel particularly interested in pommel horse, but feel free to try and convince me.
A few criteria which may help: learning gymnastics is hard so I would like the two apparatus to have similarity so that learning one helps with the other (or with floor/vault but that seems less likely). I am 170cm for about 63 kg, pretty good shoulder mobility (for a standard adult, not an elite gymnast!). I have played a bit with rings and high bar, never tried parallel bars. I feel like I would like to learn high bar the most, but perhaps parallel bars and rings have more similarities?
Thanks in advance!