Advice on making oval rosette channel

Howzit it everyone. Was learning to make a oval soundhole this week. Was able to make one using a oval template and just route out the material.

Now how does.one add a rossette to an oval soundhole?

All i can find is the stewmac purfling guide. But it seems i need a steady hand to make a decent channel.

This is for rosette and rosette channel.

Might not be applicable to your set up but in general if you use a purfling of fiber such as black white black that is the same width as your router bit (I use a .030 router bit) you can use the same template to cut out the rosette. The purfling is used on the inner and outer rosette.

You'd make the rosette channel the same way you made the sound hole. Just use a bigger oval template and set the router bit to make a shallow cut

I made one with an oval template, Using 1 in guide for the hole and 7/16 guide for the rosette 1/8 in bit.
Clamp the template to the top and do both one after the other.
This was on a mando, but same principle.