I'm joining the
jealous club on this. Awesome that you found a 10' tank in such good condition.
On another note, I don't think (based on my own experience with MCE600s) that 2 Deltec HOBs will be able to handle a tank that size, especially with your planned high bioload. The Deltecs have a rep for being the BEST hobs, but in part this is due to the poor performance of most other HOB skimmers.
For long-term ease of care, I would look at a proper in-sump skimmer setup. You could even do multiple sumps & skimmers if height (but not length) is an issue. One down pipe dividing into two sumps with 2 separate short skimmers and two return pumps combining into one return line back into the tank.
How many gallons is this monster tank anyways. My school of tangs would soooooo love this but my place is far too small for a tank this size
Anthony