Yup. If it works for you, go for it. I'll stick with vertically though. Much, much easier on the body.
That definitely says you were not at the right height. And if you are sitting right, if you do have to lift one, for example, when turning it, place the elbows on the thighs and use the leverage rather than the muscle.
I don't think it is my technique per say but more of just being at a 2ft working level. Standing on my knees would be the only bearable way for me. But then my old trick knee would probably act up. It's nice to do some hand splitting also. Partly for exercise and partly to make sure I'm still able.
I've tried it from the knees but it about kills my back. I've experimented using different heights and found the one that works great for me. You have to understand too what my back is like, which is not good. But it was great to find something that works and getting the hydraulics was the big answer for me.
I totally understand having back issues. I am ok as long as I don't do too much bending I'm usually good. I'm a tall feller, so if I get the seat height low enough to work properly, then my knees are in my chest. My first splitter went away due to a low work height. That helped a bunch. Still left me with a problem of dealing with the big rounds. The new splitter had vertical option so that is how I would bust them down into liftable pieces, then I would lay the beam down and finish them off horizontal. After a bad incident where I was barely able to make my way back to the house I swore off of vertical splitting. The addition of a Fiskars X27 gave me a new option which is how I currently operate. The Fiskars made hand splitting almost fun again for me. A hookaroon has made things even better. No more bending to pick up wood!! In the end, we all find the "right" way to deal with our working conditions. As long as it fits in the stove, no wrong way of getting it done!