That's a very difficult design to draw and/or engrave. The challenging thing when you go wrapping a scroll through or under or over another, is what to do with the leaves that were going to be there. For me that main scroll should have leaves coming from it fairly evenly along it's length.
I do like how smooth you have everything and how strong it looks, you've done a perfect job of keeping all the backbones even and attractive. Keep practicing fold overs on leaves and wrapping things through or under or over. I tend to obey the rules of celtic knotwork when I do it. Under over under over under over under over under over under over... (until i decide it's better to break my rule.)