Using too much castor oil or using castor oil with formulas high in soft oils will make it sticky. I regularly use 5% castor oil in my formulas, but my percentage of hard oils/butters is much higher than yours.
My bet is that the 6% castor with the 70% soft oil formula is what is giving you stickiness.
I would look at substituting about half of your olive oil with a hard oil (or hard oil + butters). So maybe something like 6% castor, 30% coconut, 30% palm/lard/tallow, 24% olive oil. Or alternately, you could keep your base formula, but lower the castor to something like 1-2%. I've never used castor with a high % soft oil recipe, so I can't give you a good guideline for the % to use, but definitely lower than 5%.
If you absolutely want to make sure it's not sticky, try removing all of the castor oil. But I love what castor oil does to soap so I think it's definitely worth playing with...