Two days ago? I think less than 24 hours ago. I've been working on answers for you.

First, Categories Dressing by default does not affect the categories-tabs menu at all. Many of its styling rules could be applied by adding the cat-tabs selectors to the Cat Dressing rules.

The tricky part may be getting the categories sidebox (which is what Cat Dressing controls) to display without having a visible side column. It may work to set (Configuration > Layout Settings) Column Width Left and Column Width Boxes Left to 0. Then make #categoriesHeading {display: none;} and eliminate any border or bg color in #categories {} and #categoriesContent {}.

You can make the cat-tabs work as you want right now by changing your stylesheet like this (add parts in red):
Code:
div#navCatTabs { height: 2.5em; position: relative; bottom: -0.3em;}

#navCatTabs ul
{
	margin: 0;
	padding: 0;
	z-index: 10;
	height: 2.5em;
}

#navCatTabs ul li
{
	display: inline;
	font-size: 1.1em;
	float: left;
	list-style: none;
	color: #7597A6;
	background-color: white;
	margin-right: .25em;
}

#navCatTabs ul li a:link, #navCatTabs ul li a:visited
{
	padding: .5em .75em;
	color: #fff;
	background-color: #7597A6;
	border-color: #8FBAC9 #8FBAC9 white #8FBAC9;
	border-width: 1px;
	border-style: solid;
	text-transform: uppercase;
	display: block;
}

#navCatTabs ul li a:hover
{
	color: #7597A6;
	background-color: #fff;
	text-decoration: none;
}

#navCatTabs a.category-top .category-subs-selected {
    display: block;
    padding: 0.5em 0.7em;
    margin: -0.5em -0.8em -0.5em -0.7em;
    color: #7597A6;
    background-color: #fff;
    text-decoration: none;
    }
You will be able to hide top categories in the sidebox, and position the sidebox content, using the controls available with Cat Dressing. I don't think it will be possible to disable the first level subcat links without some code modification; there may be a workaround, but I would have to experiment to find it.