High capacity? The Seastar Pro helm as far as I know is 2.0cu.in/rev and 1500PSI. It may be that you have a 2.4 cu.in/rev. helm but that still isnt enough as the side rams have alot more volume. You would end up with loads of turns lock to lock. Whats the part number HH5??? as I'm not sure if they do a 2.4cu.in 1500PSI Pro helm. With your 2.5 (engine) you need a 1500PSI helm.
Also the seastar helms need a balanced ram which the side rams are not. I dont actually know what that means I'm just quoting it parot fashion from Scream and Fly
Dont worry about the bolt loads of people run seastar pro and dont have any problems. Its a good system.