$300 worth of time effort and agg for a $79 jig and bit.
Instead of the dremel and sanding drum, I recommend a flap wheel 
In my limited opinion EPS next to outer skin is a flawed concept, regardless of the inner springers. Use the springers to waterproof the EPS core.
Ok, it’s an old one, but found something interesting and worth to share.
The template seem to be all complete in the FCS Fusion install manual. Just open the PDF in Corel Draw (or Inkscape, freeware), get the curves from the item 3 on page 1. The curves seems incomplete, but not, is just partialy hiden under a white retangle.
Already compared with a template picture and it matches perfectly!
I just need the exact mesurement of width and height of the retangle jig (the same in the picture, there seems to be some diferent ones…). Would anyone there have one to precisely measure for me? It would be great to have also the thickness of the jig and the depth of the recess. I promisse to post here the “ready to print jig template in PDF” after having those measures. By the way, which paper size do you international people most use? Letter or A4?
Ok, I agree with someone who said that it’s too much effort (money-time) for a $seiláquanto jig, but there are just no jigs to buy here where I live, so I have no other good options… even so, yes, whe are DIY guys, so why not to have some fun?! …
The manual: https://www.foamez.com/pdfs/Fusion_Manual_Final_200901.pdf
The picture I compared with: http://www.foamez.com/fcs-fusion-install-kit-jig-bit-p-711.html
Regards,
Fernando Mattos
Print this one at 100%. Should be accurate. the long side measures 97,6 mm in original.