Herein’s a repository of imagery I associate with Matamore, from Tony Kushner’s The Illusion.
I first saw The Illusion at the Court Theater in 2010. Their Matamore was played by a leading-man rather than a character actor. Likewise, he was dressed less as a braggadocio and more as a straight-up musketeer.

Timothy Edward Kane as Matamore, with Michael Mahler as “The Son” of many names, in the Court’s 2010 production. Photo by Michael Brosilow
The Court’s Matamore was also more multilayered than the script would seem to entail. His scene with Lyse in the second act showed a great self-awareness, defeat, and a quiet romanticism, rather than continued falsity and bellowing. Although this subtlety is something I hope to bring to performance as well, I no longer feel (as I once did) that a ‘sincere warrior’ costume is necessary for this three-dimensional character to exist.
The Court also gave Matamore a second, simpler (and more Jesus-y) costume for later, when his more three-dimensional nature was revealed. This means he actually appeared simpler, cleaner, and more honest at the very end, which was interesting.

Matamore’s initial costume, followed by the “honest” post-retreat costume. Sketches by Jacqueline Firkins.
From what I’ve seen, the more traditional Matamore is made up in finery and fake honors, like Signature Theater’s. Since I’m rather short (and a bit on the doughy side), a braggart costume would presumably be more successful than any attempt to dress me up like a sincere warrior. Ultimately, however, I think any costume that denotes pretension would work. Bartlett’s Matamore (right) reminded me instantly of my performance as Mozart in Amadeus, around this time last year…
Although equally admonished as a braggart and a fool, Shaffer’s Mozart is above-all a child in an adult world, and it is this attribute that I think is most charming about Matamore: a child, trying desperately to succeed in a grownup world he does not understand. This naivety of character, I think, would be nicely complimented by my short stature and relatively impish appearance.
Below is a collection of imagery I associate with Matamore. Chief among them is the Onion Knight, an inept child-warrior of exaggerated appearance. This, more than anything, is how I see Matamore right now: a little boy playing at manhood with exaggerated finery. I particularly love the plume and the pantaloons, but that’s just me.

Leviathan. “Trullish chambermaid, do you think That such a gross Leviathan as myself would stoop To spy upon my future Queen?”

Fiery Heart. “The Queen of Iceland?” “Will not let me rest; pursues me in her sled; And wants my fiery love to thaw Her frozen marriage bed.”