I went straight to purchasing the killerbee from Marc Bailey. It's an issue of time vs money, if you have one but not the other you can still get where you want to go. If I had started with pastel x spider hatchlings, it would have taken years (and some luck) to hit a killerbee.
And I felt that bumblebees will sell well, so I wanted a bunch on the shelf
A spider x super-pastel will give 50% bees and 50% pastels but no killers, unfortunately. A bumblebee x pastel will give 1 in 8 killers, statistically speaking.