You might want to consider triples instead of duals. They take up the same floor space, have better performance, and will visually match Maggies better. If you go with duals, be sure and use the 16 ohm drivers. That way if you want to add a 3rd driver down the road it is easy to do.
Here are some pics of a pair of triples I built for a client in Chicago paired with his Martin Logan Summit X speakers.
These are actually taller than triples normally are. This is because the amps have been built into the cabinets under the bottom driver. I'd stick with the amps in separate boxes behind the subs. Much easier to build and handle.
Jay's flatpacks have a number of options including overhang or no overhang on the top piece and grills. His flatpacks are easy to put together with a minimum number of clamps. Peter has a YouTube video showing the process. DuraTex is easy to apply, is rugged, and will give you a flatter finish. While parallel clamps are nice, they are expensive but there are less expensive options such as bar clamps and ratchet straps. Something to think about anyway.