I'd recommend following the manufacturer's recommendations. The information published has proven to work and work well. The manual likely suggests a known deflection for each surface. I would setup my linkage to provide these " knowns " with ATV/EPA's within 10% percent of the MAX settings and determine the need for more less from there. My goal would be to obtain these " knowns " with as short a servo arm and as long a control arm as permissible.

I like precession servos be it analog or digital, my personal preference would be for the digitals.