If all you are looking for a single level horizontal navigation (like the one at WebAssist.com) you should be able to achieve a simple version of that without using CSS Menu Writer to create the preset first.
The default menus that are available in Site Sculptor use a semi-transparent image that creates a gradient effect. Then, in the CSS a color is applied that makes it easy for you to switch to any color you want from within Theme-it. However, let's say you didn't want the gradient, you can go to the Manage Images tab of Theme-It and remove that image. Leaving a simple navigation with just text and a color.
Now, if you don't want the dropdowns for the additional levels, you can select the "Do not include this page in the navigation" checkbox for any pages that are subs of the top level.