Hi, well, neither are right, actually, they are both half right. You need to focus on toes up, rather than heels down, because doing that makes you push down into the stirrups. You shouldn't need stirrups to post. Using your stirrups to post at first is okay, because you are trying to find the horses rhythm. What you need to do is drop your stirrups and cross them over the saddle, and post without them. NO, you don't need to focus on posting up, you barely have to clear the saddle. There is no need in seeing how high you can post. Go back to your "up and forward" style, but without shoving your feet in the stirrups, and you will get the hang of it. The main thing is posting without stirrups, you can get a trustworthy trotting horse and maybe someone to put you on a lunge line so you can practice. Or just go bareback, whichever way you are more comfortable. Posting should be done with your thighs and they will hurt really bad, but after I rode bareback and without stirrups for the past 4 or 5 years, I can go on and on and on...so it does pay off, and some equitation and medal classes do require w/t/c without stirrups. Good luck!