To cut the tapers , use a  plywood sled. Extend the lines marking the sides of your jig to points "A" .  Use these marks and some carpet tape to fasten the work piece to the sled.  Cut one side, turn the work piece around and cut the other.
Drill holes for the screws using the base plate of the router as a layout template, mark

You can make your own jig for routing curves with your router.  The material needed consists of three or four screws to attach the router to the jig, a piece of scrap 1/2" plywood , and a 1/4" dowel..  The width of the work piece should be a little wider than the base of your router, and about 32" long for most applications.
 

the positions of the screw holes to fasten the router to the jig.  The 1/2" hole in the center of the base plate was made

using the plunge feature of the router.
Measure from the edge of the bit to the center of the radius, and drill a 1/4" hole for inserting a dowel for a pivot.  This jig has been used for 4 different radii.  The hole for the pivot does not need to be on the centerline of the jig,

Layout the jig using the router base plate to mark one end and a drinking glass or coffee cup to mark the curve on the other end.  Then draw straight lines tangent to the curves to mark the sides of the jig.

 

only at the proper distance from the router bit for the curve you want to route.  Enjoy using your new home made jig.