Make a 16:9 Native screenmode?

[Ral-Clan]

Is there any way to make a native chipset (i.e. ECS) screenmode that would be in a 16:9 ratio?

i.e. one that could be stretched to fill a 16:9 monitor but still be the proper aspect ratio (so icons wouldn't be stretched horizontally)?

I'm thinking something along the lines of 768x432 or 608 x 342?

Making new screenmodes has always been a mysterious thing to me - I have no idea of how to start.  I've played with the built in screenmodes in Preferences, but I don't even know how to save a "new" custom screenmode without saving over top of one that already exists (which I don't want to do).

Then there's the whole non-square pixel thing I haven't even begun to throw into the mix.

[Ral-Clan]

1280x720/1280x768 is an option on my laptop so 640x360 or 640x384 is the same. Therefore 640x400 in 60hz full screen would work well and is very close.

Trouble is the Workbench icons were designed for 640x200 or 640x256 which is why it looks wrong.

But how do you actually make a new custom screenmode?

When I open up my screen preferences, I am given a bunch of screenmodes depending on the monitor drivers in my DEVS folder.  I can tweak these, but if I choose SAVE it writes my new tweaks over the original settings for that screenmode.

There is no "SAVE AS" to create a new screenmode from within Screenmode prefs.