I really like the body shape, for the record. It's unique and coherent. Many builders start out by doing carbon copies of famous designs, which is great in it's own right of course - but I always love seeing builds on here where you can really see the builder's own vision, versus them just using tracing paper on someone else's vision. To me, that's the whole point of building - to make something that's all yours.
The way I do my magnetic control cavity covers is to do a full cavity route, the actual outline of the cover (without leaving a ledge for the cover to sit on), except two or three little "islands" to which I stick the magnets. I position the islands towards the middle, with the ends of the cover unsupported. This way, I don't need a finger slot - to get the cover off, you push down on one of the unsupported ends, and it levers the cavity up off the magnets.
And in most cases, what I've done is to glue magnets to the back of the cover, and then use a small flat head steel screw or bolt into the island inside the cavity for the magnet to stick to. This way, the depth of the cover is adjustable by turning the screw. This lets me fine-tune and get a perfectly flush cover. Although what I usually like to do is have the cover ever so slightly recessed, so there's less chance of it getting caught or knocked off by something.
I like to do magnetic truss rod covers, too. You can bury a small magnet in the very end of the truss rod slot for it to stick to, and then no screws show. For wood truss rod covers, I like to laminate two layers of wood veneer to the back of the cover at opposing grain directions, to sort of create a mini plywood effect, to help reduce the chance of the wood splitting from being pulled up to release the magnet.
I was a little nervous when I did my first magnetic covers that they might not stay put but they've done really well, including holding up to my guitarist doing his "flying crab dance" while playing a guitar I'd built on stage. That's good enough for me!