Step 2 chance to get one or more rainbows: ~43.2%
Step 3 chance to get one or more rainbows: ~68.7%
Combined chance to get one or more rainbows in either or both step 2 and/or 3: 82.1%

Considering that there's a fair chance to get multiple rainbows, it's a pretty good deal. Considering that there's also a fair chance to get no rainbows, it's a pretty bad deal.
I wonder what Moarsi does. ADD SALT, Moarsi, YOU CAN DO EET!