I think your raw photos look good, doc! The full body shot is really the only one that needs help IMO. It's difficult to get a good reflection from a white object.
I photoshop my stuff quite a bit, mostly with levels, brightness and contrast. You can get a gray background to go black with a little practice. The contrast between background and the bass helps a lot to make it pop.
I also use a manual digital camera (Panasonic LX5). It allows me to set exposure and aperture if I need to. Mostly I just use the lightness/darkness function. A tripod is a big help.
From the camera. I clipped the edge of the Ebird so I hadn't used this 2 year old image until yesterday. It's also a little blurry.
Sharpened, color corrected and background extended.
Cut out and dropped into another corrected and extended image.
Sometimes it can be more fun than building the stuff!