I shot my Kodachrome 120 at an EI of 12.

Here is the process I used:

1. Rem-jet removal bath 2:30 (you can go longer, it won't hurt)
2. wash (vigorous agitation) 3:00
3. Develop 6:40
4. stop bath 0:30
5. fix 10:00 (I used Kodak Fixer)
6. hypo-eliminator 2:00
7. wash 6:00
8. bleach 2:00 - 3:00 (depends on strength of bleach, could be up to 8 minutes)
9. wash 2:00
10. fix 5:00
11. hypo-eliminator 2:00
12. wash 6:00
13. photo-flo 1:00

For the developer I used HC-110 Dilution B at 65 F
The bleach I used was the ferricyanide bleach from Kodak Sepia Toner.
The remjet removal solution I used was 100 grams of Sodium Sulfate and 20 grams of borax in 1 liter of water
I normally use stainless reels and tanks. Before the bleach step, I switched the film to a plastic reel and tank.
The negatives were easy to print and had good tonality.