I owned all three products Scott, S3DP2, Rambrandt and Zobian controls SUPER Rat.
The Super Rat was actually just an after-market generic mouse that came in two styles. One, as seen in the Super Rat ad looked like an Amiga mouse, but was really made for the Atari ST line (Amiga & ST mice need button rewiring to work on the other's machine). The second style that I got was a similar two-button ST compatible mouse, but was a more rounded and ergonomically shaped. And it did NOT work with either my latest revisions of S3DP2 or Rambrandt. I found out later, in more recent years, that the original Rat that had one button, black case and brushed metal top plate with RAT printed on it was in fact not a real mouse, but a device that used the Pokey's Pot lines (not optical sensors, and wheels with grey-code like real mice or the Atari track-ball in true track-ball mode))and worked in a similar fashion to the Atari touch tablet and Koala touch tablet, and I guess also had a "joystick mode" switch like one of the Atari track-ball versions. So it would work with Rambrandt if the software was set to use those devices and S3DP2 was programmed to use a joystick only, and IIRC, only in it's graphic editor mode, the other modes used strictly keyboard presses for manipulation or commands.
I still have my "Super Rat" real mouse, which did work with the software that came with it, accu-draw high-res drawing program and a very simple and ultimately pointless GUI that worked with DOS 2.5.
Of course there are other classic and newer (post 8-bit era or PD software) art programs that can take advantage of my real "Super Rat" mouse.
For Rambrandt I always used a touch tablet after that. I use the Atari track-ball in joystick mode for S3DP2's graphic editor.
I was also able to use my "super rat" mouse with Diamond GOS when it came out a few years later.