My observations when starting out was that matching fin buoyancy to my body and rig's trim needs was critical to maintaining proper trim. With experience and training I found that I could dive in good trim regardless of what find I had on. However, perfect trim still requires excellent weight distribution, and that is very personal. Enough sleuthing will reveal the buoyancy of many fins. If you need a more negative fin the Eddy's are out. RK3 HD's, Hollis F2 LT's, and Dive Rite XT's are all options.