[bret]

When designing from scratch, I tend to prefer a non-trunnion mount, but that is just a personal preference.
Under NO circumstances mount the trunnion under the plate it WILL fail. That 4000 proof load assumes a perfect loading pattern, perfect torque, and a steady linear load. a large pothole that bottoms out the suspension could send a 4G load through those fasteners. Your 900 lb corner weight with a 2:1 motion ration would mean that coilover needs to support 1800lbs steady state. 4G x 1800lbs is 7200 lbs. Bad things will happen.