Bond makes the best built derringer on the market, I have a Cowboy Defender 45/410 three inch and love it. My leather holster holds the gun up like a tape measure on my belt. I carried mine every day for about six months then switched it over to a Smith J-Frame 38+P, Model 642 Airweight.
For carry purposes I used Buckshot, I like the multipule lead balls over a single projectile of the 45 colt or the 410 rifled slug.
The 410 PDX ammo isn't good in the Bond because the barrel is to short and the twelve BBs spread out to far. My Bond with the PDX ammo the BBs were off a 4' X 4' sheet of cardboard t twenty-one feet.
If I were to buy another barrel I think I'd go with the 38spl.
My friend liked my Bond and went to Cabelas and bought the Texas Ranger gun, 4" 45/410 and then bought the 22lr barrel and the 9mm barrel. He bought it a couple of years ago and still carries it every day. He has the cross draw holster like yours.
I'll never sell mine, it's a great little gun, I occasionally carry it in my coat pocket when I go to the casino or to the store if I don't want to carry my revolver.
(Are you shooting 3" 410 shells in a 2&1/2" barrel?)