..the Olympus SD-510UZ seems to be a 2006 upgraded version of my C2100. The manual focus, aperture and shutter speeds will help get better model photos. I don't know if the remote control Olympus sells will work on the SD-510, I know my C2100 had one and it makes a whole lot of difference.
I used my C2100 until 2008 when I bought a Sony H-50. The only reason I bought the H-50 was due to yellowing of the images on the C2100. That and the fact that the camera was falling apart from the milage I was putting on it. If the C2100UZ worked for me for so many years, the SD-510 should work for you in a pinch.
The number one thing I look for in a camera is manual control. That way I can control everything. #2 is the remote control. Need to keep my grubby paws off the camera to prevent shake. #3 is a flip up LCD screen. Seriously, with the flip up LCD screen, I can put the camera low on the model, and still sit comfortably upright and still read all the camera settings on the LCD. With the C2100, I was often sitting on the floor just trying to read if the EV value was right, or the MACRO was on and so forth.
When I bought my C2100UZ back in 2001, I wrote 10 articles about model photography as I learned them with the C2100UZ. If you are interested, I can e-mail you these articles in PDF format. They are written from the viewpoint of a young female modeller learning learning from an experienced male modeller, so photos of the young woman pop up once in awhile.......
Let me know if you are interested and I can send them to you.