This is how I went about making the aprons.

 I used my favorite jig material - MDO 1/2" double sided. I Prefer MDO because the paper surface and ply edges will outlast MDF in the long term. The surface remains slick for the router bases to slide smoothly on. ( And because I had just the perfect piece of MDO scrap piece ) 
 I'll use MDF also.

  Made the curve line using a scrap piece of thin maple to use as a batton and sprung the line.  Cut on the band saw and finished to line using a spindle sander. Then smoothed by hand sanding.
The two counter sunk holes near the center are used to hold the stock by temp screwing into the back of the aprons.
   
The four outer c/sinks are for screwing the assembly down onto the sacrificial mdf board. Like a clamp.
 



The underside has some thin strips about 1/8" of maple to position and hold the apron in place snug.
And the Grex pinner and a little glue was perfect to get it together.



Apron in place now to secure for routing. ( yea it's already cut in this pic ) but it started out as a full width board. No pre cuts on the band saw.


The assembly is secured to the bench with clamps. Looks more complicated than it is.
The OF 1400 along with a copy ring and bit was used to make mutiple passes to cut the pattern in the solid teak ( looks like ply in the pic )


The copy ring offset measurments were calculated into the jig prior to cutting the jig pattern, so as to have the apron finish out as shown.