Nancy Bush demonstrates the Estonian cast on used in this sock here: http://youtu.be/Frc5_9AIVy0
I did the cast-on with double yarn as suggested. But you end up with the regular tail from a cast on plus not one, but two loops. You get an annoyingly short loop from releasing the slip knot as instructed. The instructions say blithely to cut this yarn off. But the cast on would surely unravel. Those two loops are not that easy to anchor, the short one at least.

So I cast on again and this time I counted the double slip knot as two stitches (to solve the problem of the recalcitrant little loop). I then cast on 66 stitches for a total of 68 because as well as the cast on issue, I found 76 stitches much too roomy. I removed a total of 8 stitches. I took 2 stitches out of each 5-stitch stockinette panel flanking the cable panels on the instep. I took out two K1, P1 ribs (= 4 from the back of the sock). This way I preserved symmetry within and between the back and front of the sock.

When working the heel, it was just necessary to subtract four from the total count. I knitted till I had 16 slip stitches instead of 18. This preserved the proportions of the sock.

I had never worked a Dutch heel before and was a bit confused. This video cleared it up for me, as well as the explanation earlier in the book.

I love this heel, and detail added by the designer: the column of 2 stitches in garter followed by a purl stitch on purl rows and kbtl on knit rows gives a beautiful, tight pick up on the first gusset round.