Most Multigrade papers come with a table showing paper grad versus colour filter, say Magenta 200 for grade 5. In general there seem to be two types of colour heads, with slightly different filtration. Using multigrade paper the contrast is controlled at the printing stage. If you use graded paper you might want to use about 20% more developing time as for condensor to increase contrast. (Which is reduced at the printing, as John said).(posted 8676 days ago)I think Ilford is selling books on their Multigrade papers (one for RC, one for fibre)have a look at them, or contact their website and look at the data sheets.
Agfa gives dev. times for a contrast of 0.65, which is closer to the diffusion enlarger. Fuji Neopan 1600 usually gives high contrast for diffusion.
Regards,
Wolfram