Sounds like you're in good shape with the rheostat and the fuel tank screen.
On pulling the instrument cluster:
I have a picture on my other computer of a tool that someone made for this purpose. It sounds as though you already know what you're doing, however, if you like, I can e-mail it to you within a day or so (post your e-mail address if you'd like). Also, you might be interested to know that for my M-B (300CD), I have been able to remove the cluster without using the the hook tool. Essentially what I did was to remove the panel above the driver's feet and just use my fingers to gently push the cluster out. For all I know, the hook tools make the job easier but for what it's worth, I did it another way.