FWIW, I rarely used the specific grade "equivalents" when I switched from discrete, under the lens filters to using a colour head on my Beseler 67.
The chart referred to on Ilford's site helps you at first, because it gives you a feel for how much adjustment is needed to make a meaningful change, but the speed matching is usually of marginal value, because it is dependent on matching a particular mid-tone, and the mid-tone I want to match varies from negative to negative.
The great advantage of the dichroic head is, IMHO, its ability to supply an almost infinite variety of fine adjustments to contrast.
I'd suggest to the OP that he/she start with the suggested setting for grade "2" from the Ilford technical publication (using the Beseler/Kodak numbers) and a negative of known "average" contrast. And then tweak from there, if necessary.
EDIT: Just to make sure that we are talking about the same thing, this is one of the publications I am referring to: http://www.ilfordphoto.com/download....8932591755.pdf
The paper also includes a slip with the same information.