If run at 100%, the Radions will be closer to 900 watts.
Pull the T5s from the Giesemann Spectra and drop in 2 XHO bars. They should retro in clean and not ruin the gorgeous look from the Giesemann and you'll use half the wattage, all while eliminating the bulb replacements.
IIRC, the Spectra is single end and that is 100% the way to go. Radiums are my favorite SE bulb ever but I've been using the ReefBrite 20K on my new build. You can see pics of my light rack in my build thread. I'll have updated pics of everything soon. Waiting on a replacement halide bulb from ReefBrite that broke in shipping.
Truth is the halides will last 14-18 months before they need replacing and you will have THE best light on the market. Period. You will never have to guess or wonder if lighting is your issue. No apps to frustrate you. No sliders to screw things up. Just set it, forget it, success.