Concrete data on running SE bulbs on HQI ballasts (or any other type of MH combo for that matter):
http://www.reeflightinginfo.arvixe.com/
I have an 18" deep tank running a lot of friggin' light as you can see from my sig. I keep my crocea clam on the bottom no problem. Some of my LPS bleach even down on the bottom so I have to hide them in shadowy areas.
SPS should be placed up high regardless since that's where the wide open flow they prefer is located. Look on any natural reef - the SPS are always located at the reef crest.