Glad you found Isaac's blogs posts at Blackburn tools. He's got great info on every step of the saw building process, handle-making included.
I will say that a saw handle is a complicated project if you've never made anything with rasps and files before, but hey, one way to learn to swim is to jump right into the deep end. On the handles I've made, I've normally started by sawing out as much as the profile as possible with a band saw, coping saw, bow saw, or whatever you happen to have. Then I do most of the stock removal with rasps and follow up with files and sandpaper. On your first handle, try to keep as close as possible to the pattern. There are good reasons these handles are shaped the way they are. But you can, of course, modify the pattern a bit to fit your own hand.
One of the big challenges is work-holding. I highly recommend a large handscrew held upright in a vise. If you hold only one of the handscrew jaws in the vise, you'll be able to adjust the handscrew on the fly. In the picture below, my vise racks a bit, so the handscrew jaw on the right just swings free.
Here's a link to the first of a series of blog posts I did about saw making:
blog post.
Not quite as instructive as Isaac's blog, but you might pick up some tips from another guy who has less-than-optimal tools for this kind of work.
[url=https://literaryworkshop.wordpress.com/2014/08/23/building-two-saws-part-1/][/url]