Do you really need a jig to mount these bindings? Isn't there a template/guide provided somewhere?

http://www.wildsnow.com/articles/dynafit_mount_2001/dynafit_mount_2001_1.html

Easy trick for finding ski center if you don't have a jig...take a piece of paper, lay it over the top sheet and down the sides and crease them over the edges, remove and fold in two using the two crease marks from the edges, line the crease marks from the edges back up onto the ski and voila, the middle folded mark is your ski center.

If you're mounting on newer Dynafit skis like the Manaslu, mounting can be done (carefully) at home in the pre-drilled holes. Just grab a pozi-drive and a beer and it'll take about and hour if you're being really careful.

I would say the key to using the paper template is making sure (and then checking three or four times) that you have the centerline perfectly marked. That is the hardest part. Also make sure you have the right bits to drill into the skis. Smaller diameter for wood core, bigger diameter for metal. That is a mistake you won't make twice

If you're very capable (and careful) with woodworking in general, and download (and read carefully) all the material from WildSnow.com, then you can mount Dynafits accurately by yourself without a mechanical jig. I think my first attempt that way took about two hours. After that, subsequent mounts took about an hour. But once I bought the mechanical Dynafit jig, mounts now take only about twenty minutes.