I am 5ft and weigh approx 8.7 stone. My friend is a bit taller than me and probably weighs the same although cos shes taller she looks much thinner. My RI let her ride an 11.2 nearly all the time a few weeks ago but she says i am too heavy for her. Also, she keeps putting me on a 16.3 but im not sure if this is because nobody else rides him atm or cos im too heavy for anything else? What size is really suitable for me? i would have thought 14.2-15h would be fine? What does everyone else think?