I just recently tried Arista/Foma 100 in Ilford DD-X with beautiful sharp results and a full range of tones. Use the develop times printed on the Arista box for TMax 1+4. I prefer DD-X at 1+9. Simply double the DD-X 1+4 time. And as always, your results may vary so don't try this with anything important yet.
I use it at box speed. DD-X at 1+4 is too hot.