Not sure if this is an answer to your scanning issues, but there is no problem scanning grayscale film (easier problems than color scanning), however printing grayscale photos on an inkjet printer can suffer a bit.

Your size comparisons do miss some points. If uncompressed, 8-bit mode grayscale data is 1 byte per pixel, and 8-bit mode RGB color data is 3 bytes per pixel (one byte each of Red and Green and Blue channel, called 24 bit color)... just how real life is. Color is simply 3x larger data. So 20-30 MB grayscale would be near 20-30 megapixels if not compressed, and only 1/3 of those megapixels if uncompressed RGB. That is not a meaningful quality comparison, however color is generally considered to be a plus.

And TIFF data is often uncompressed. TIF LZW compression is available (in photo editors, but not so much in scanners), but it compresses only a small percentage as much as JPG compresses, because LZW is lossless, but JPG is lossy (you could say, an approximation). Selecting a HIGH QUALITY JPEG setting is a larger and thus better quality image.

I'd say just wade into the scanning if you're willing. A thousand scans is a lot of work in any situation. It can be faster to use a digital camera in a macro slide-copy situation, if you have a way to hold the film and light it from the back side. Using the scanner film holder to hold it might simply it.

It is true that presence of metallic silver in the emulsion prevents Digital ICE from working, because silver is "seen" as a solid, same as dust or scratches would be seen (all color film except Kodachrome are dyes, with no silver). ICE removes visible spots that are not dye based (because infrared does not see dye at all).