But i am perplex :)
here that i obtain by _import OBJ your file by Max Smirnov

What is your method now for fill the "gap" ? Some are overlaping...
You kill faces...& redraw a vertical rectangle... or Polyline+ plane or...

Just redraw or extract "Profils" for make surfaces ? There is a missing link in the general process! :)
I surelly miss something!