Speaker stand height

Here's another idea which is unconventional but you might love the sound of it; turn them on their side, like a center speaker. You might be shocked at how the sound changes when they are turned, let's say, on their side with tweeters inward. That change in elevation of the tweeter of several inches may do the trick, and the placement of the bass outward and tweeters inward is more like a panel speaker. Give it a shot and see what you think. Costs nothing and you may like the sound a lot. Also try them with the tweeters to the outside and you will likely sense the soundstage has widened a bit. Of course, then you can also work with their placement, distance from each other as well.

You can also take a couple rubber washers or similar - or better yet some stick on rubber feet or blue tak, and set the back of the speaker up ever so slightly, moving the directionality of the speaker downward. Between these two ideas you likely could find a solution without having to buy new stands.

Manitunc's suggestion of turning them upside down is also a good one. Once or twice I have taken modular speakers costing tens of thousands and turned the upper module containing an inverted driver array upside down to see what the speaker sounds like when the drivers are lined up more traditionally (smallest to largest from the top), a very enlightening experiment.

There's plenty of things you can try. Sometimes it's fun, even when you have your optimal positioning, to turn them on their side just for kicks/variety. :)