ok good.
Looking at DCC's pics I noticed the underside of the tank has NO mounts on it, so it is up to you to figure out how to mount it. The first question I would ask DCC and Legendary is if they have the honda tank mounting cups sold seperatly and could those be included in the sale. Since legendary is the manufacturer they might be more likely to be able to supply it. In looking on ebay at the various people selling the legendary tanks, some of them come with the norton screw down mounts which will not work for a cb750. DCC is showing pics on their website of a cb750 with the tank on it so ask them for pics of how they mounted it.
If it were me I would do it one of two ways:
1) Tank strap. All the race bikes I ever worked on had long padded strap that ran down the spine of the tank. Since the tank cap is dead center on the tank this may require a creative option, original manx tanks have the cap offset. You will probably have to fab this but it is just a strip of aluminum that you keep under tension, unity equippe sells original straps for manx nortons but you may need to check size and fitment since the legendary tank is a look alike and not an actual replica.
2) find a #$%*ty tank, cut the mounting cups off it, and bond them on to the tank with epoxy.
Something else that concerns me is that the original manx tanks had cutouts to keep your hands and clipons from bashing the tank. These do not have those cutouts and all the cb750s I see on the web using this tank (and there are not many) are using clubman bars which are higher and more forward. Something to consider if you plan to run clipons and should probably ask about.