A major issue would be how well the real world T/S parameters of your ANs relate to any specific enclosure design. It would be helpful if you're able to measure them yourself after break-in.
Like many of his more elaborate designs, IINM, Steve's HDT was finely tuned over an extended period of time, and is not as simple a build as most on the CommonSense site.
Not all enclosure designs can simply be adjusted to suit drivers of larger size and presumably lower Fs - you might be able to fit them in the boxes, but having the system perform its potential is another story. I'd suggest you contact Steve directly with your questions.