Sharpening curves

[Indoorsout]

I'm fine at sharpening straight edges, learnt that on planes and chisels when I worked for a shopfitters, but how do you sharpen a curved edge properly? I always have trouble sharpening the curved end of the knife and it looks like I'll be getting a Nessie soon.

I have a set of 3 diamond hones, coarse, medium and fine, and a set of smaller diamond hones for field use. Got plenty of leather for a strop but no stropping compound, do you really need this?

Thanks
Indoors