I have the incuview and am happy with it. Mine does require some babysitting, but I feel that is my fault. I have it in the utility room and there’s a lot of coming and going to the garage, so the room temp is unstable. It’s a convenient spot for me, though. A little fluctuation is not a huge deal. Mama hen isn’t perfectly uniform either. You just want to avoid over-heating or cooling them for a long enough time to change the internal temp of the egg. I don’t know how long that would be, but my hatches have gone well so far. I have some of my own in there now.

Ten days to go... So far, so good.
I was concerned about the lay-down egg position too, but in two hatches of shipped eggs, every egg (but one) that began to develop, hatched a healthy chick or duckling. The one that didn’t, failed early. None of the air cells were stable. What I did was set them (at temp) broad side up in a paper egg carton for the first couple of days. You can fit two of these in the incubator with the turner removed. After that I put in the turner and placed the eggs inside the rails.
Whether that helped I can’t say, but I don‘t think the non-developers were the incubator’s fault. IMO they got knocked around too much in shipping or weren’t fertile to begin with.
I don’t know whether you could rig this incubator to accept a conventional turner. People do all sorts of amazing things, but I’m not handy with machines. I think you’d probably be into it for more money than you wanted to spend though, however inventive a person you might be.