With color negative printing you will always be able to get a usable filter pack with Magenta and Yellow. I usually print at 65 Yellow 75cc Magenta. There is simply no need for a cyan filter because you will always be balancing away from cyan.

I think if you had a baseless film you would need more magenta and yellow filtration to give the film an apparent orange base.

I needed Cyan filtration once with fuji paper that was crossing over itself backwards.

The filter pack in Ilfochrome serves only to correct for variances in the paper. You calibrate it to achieve neutral greys and then you're done unless you want special effects.