The reason I am looking at an emi filter is the noisy environment I have here within ~1 meter of my bench. 2x (109cm 4k monitor, keyboard, mouse, 600watt computer SMPS), a fan, three wall warts, an RF amplifier, a laptop, a portable AC unit, soldering iron, several LED task lights, HEPA filtration system, and what ever other thingy I am working/playing on.
Having a linear PS in a shielded metal case will, hopefully, stop me from having to investigate emi on whatever I am working on and I will be able to get rid of some wall warts. Or maybe I am just paranoid...
on the plus side, Benta was correct I believe, as adding another stage to the packaged filter cleared up the problem in the simulation that was being caused by the coupled inductors. I just didn't expect that to be a problem with a packaged filter and my sim does not resemble their insertion loss graph.
As the manufacturer says in their datasheet, "the best way to select and qualify a filter is for your engineering to test the unit in your equipment". Still not sure I trust this sim, but it looks ok now.
Thanks everyone for the responses.
Not looking at perfection, just for it to be close.
Mclute
(I did change the graph to DBu as it makes it easier to read, but the spike is gone.