The only problem I've had with spacers instead of a plate going underneath the shell holder is there is then nothing to hold a shell in place and help it out of the final crimp die. You'll notice the shell holder has a lip on the top where a shell goes in and on the underside a lip to keep it in place when you lift the handle after the final crimp. Without both, the shell wants to stick in the die when you lift the handle. When using a 1/4" spacer under the shell holder you'll loose the bottom lips ability to keep it down on the press. I run a 1/4x20 machine screw through everything [spacer, shell holder, press plate]to keep it tied together. On my old press it has a tapped 1/4x20 hole in the back of the press, like it was made for it. Maybe I just don't know how to use the spacers. Maybe someone could tell me how you get a shell out of the final die when using spacers. I like your shell cutter. Did you make it yourself ? You probably already knew, but a navy bean in with the shot would have made your load work without the cutting the shell down.
