QTR-Quadtone RIP

I've been using QTR to produce platinum prints for quite a number of years and I am very impressed with the match I now have between my screen and the final print.

Recently, I've been pondering whether or not it would be even better if I could soft proof for the colour of the process too. For example, if I wanted to look at an image on my monitor as a straight palladium print, developed in potassium oxalate on Arches Platine I could just apply a pre-calibrated RGB curve to the image to see if I was satisfied with the tones of the proof before finally committing the image to paper.

I realise that this may require a few test charts for each combination of variables. But could anyone help me with the practical part of measuring and creating the appropriate RGB curves? I do have a scanner but would prefer not to have to but an expensive colorimeter.

Many thanks!   

--Tony McLean