Do you have access to Photoshop? I have found LR not really suitable for the task, but a combo of LR and Photoshop to be perfect. Basically, my method is similar to the Photoshop one in the article, but with a few differences.
For mask removal, I take a copy of the image (cropped without frame borders) and blur apply blur > average to that layer. Invert this layer, then set it to something like soft light or vivid light. This should remove the bulk of the cast, assuming you don't have an image with a particular color through all of the frame. You could also probably get a library of colors to mask with based off of film type. That said, it may or may not lead to more time spent color correcting than the article mentioned. The cropping also allows you to (assuming you imported into PS as a smart object) adjust your black and white clip points to the negative itself.
Of course, this partially falls apart if you are stitching, unless someone can tell me how to stitch two+ RAW files together....
