Blower psi-d@72 or hi-helix@40

Hi all
If you had to choose between a psi-d screw blower@72%
or a hi-helix@40% on an iron block bbc, what one would you
buy?I really dont want to spin it more than 8500 or less.
Which one should give the most boost at those rpm?
Thanks in advance.
Joseph.