I have some 630 dual bulb fixtures at another place I can’t show and I have run double ended 630 here and I think they are alright but I really like the vertically mounted 315 cmh fixtures out of all the cmh choices. The hlg 550s are very comparable to 2 315s sitting side by side. That being said, in the new buildout I will go with double ended hps supplemented with a few 315 bare bulbs hanging in the aisle. The cmh are my favorite for veg. The size of the space you have to light would be a big part of choosing what lights to run.