If I were you, I'd do a little experimenting. Maybe start with one tablespoon per every four ounces. There's no question that the HDA will add durability to your bait, but only you can be the judge what it does to the movement and what is, and what is not, acceptable to you. Hopefully, you will be able to come up with a formula that not only provides the movement you want, but also the durability you want.
Another alternative to the HDA is mixing soft with medium plastisol. Maybe that will accomplish what you're after.