I checked out some You Tube videos on various caliber Bond Derringers and notices some said the trigger guard was banging their finger on the .45 ACP. Well that sounds like Seacamp. However, the trigger guard is removable on these (but not so on the Stinger). I would get the .45Colt/.410 Rowdy but for shooting .45 Colt you get a measly 1/2-inch of rifling. No wonder I saw reports of key holing on that one. Yep, best to stick with the .45 ACP. It is a fairly large gun and if need be, the larger grip will resolve any issues with recoil. Or just wear a glove during practice. Yeah, I was getting a little spooked on the .45 ACP but there are women shooting them on You Tube with no issues (smaller hands so probably not getting trigger guard bash).
However, Hickok45 did not like the .45 ACP and basically says if you want to enjoy the gun,
go with the .38 Special. Wise man, maybe I will take his advice. Can always get a .45 ACP at a later date if I really feel the need/desire, and a longer barrel might mitigate some of the recoil.
As for the ejector on the .38 Special. I see a screw, so presumably the ejector could be removed to simplify removal of the spent cases. However, it is also chambered for the .357 Magnum, so that pinches the rifling down to a little over an inch.
But as far as maximizing rifling, which presumably will help accuracy, 9mm and .380 are the best, and since I already have a nice stock of 9mm, that would be a good way to go. With 9mm I get 1.75 inches of rifling.