The Radiance will do a better job of upscaling anything that is not 1080P. The Radiance CMS is mathematically correct. I don't think any of the projectors are mathematically correct. With meter and software, you can also do auto-calibration.
I would get another RS4800 and use a triple stack if you need more brightness. I would also get a device like this: http://airflex5d.com/products To help line them up. I would probably run two for 16:9 and three for 2.35