I also use 64T for artwork. I use Kodak, but the current Fuji emulsion is on a par with it - the old Fuji 64T was not nearly as good.

For colour accuracy when the silde is not intended for projection to an audience, I include a grey scale and colour scale (Kodak 'Color Separation Guide and Gray Scale', Q-13 small and Q-14 large as mentioned above).

Most of the time I use more than one light, so I adjust the colour temperature of the lamps to be uniform, using fractional CTB (colour temperature blue) or, rarely, CTO (... orange) gels.

In extremis I also resort to the old crossed polarising filters trick (one on each light in use, one on the camera) but that really is a last resort.

Best,
Helen