Andy - I'll try to fill in some blanks. And this piece of history may interest some of you.The 3-D baffle is a rather difficult item to produce one-off. The 03 had a flat baffle and the 03a added wool felt around the drivers which worked very well, but seemed somewhat inelegant with our high-WAF furniture-presentation. So I devised the contoured wave-launch baffle which, I believe, was unique at the time. The CS3 (1983) was made by hand, assisted with power tools. First the laminated baffle was beveled on a tablesaw to remove excess waste. 45° across the top and 45° x perhaps 15° up the sides. The CS3 was then shaped with a hand-plane and random orbit sanders to its final contours. The CS3.5 (1986) was contoured with a form tool in an inverted router as follows. The excess waste was removed by tablesaw just like the CS3, then the CS3.5 was machined on an inverted pin router: fixtured in a jig, back-side up, where the jig interfaced with an overhead pin centered on the underslung form tool, which was an 8" diameter arc to shape the rounded edges. That semi-manual method produced the early 3.5s. Later, that forming operation was moved to the Computer Numeric Control Router to the great relief of all. The CS2.2 (1990) used the same tool, but was designed and manufactured entirely for CNC Router.
You might consider the CS3 method of table-sawing the compound angles on the sides and the straight 45° across the top and then shaping with a hand plane, sander and an arc pattern to guide you. Divots or other errors can be filled with body putty (Bondo); and paint covers a multitude of sins. You might also know a CNC job shop to carve it, probably with a ball-end mill. You then remove the swarf with a sander. Or take the Avalon (etc.) approach and make facets without the smooth arcs. I think I would do that and cover the facets with F11 wool felt to absorb the migrating launch wave. I am presently having great fun with felt on the curves and believe that felt on facets would be a good way ahead.
Have fun. Keep us posted.