I used to mix a scratch batch of this warm tone developer for use with Ektalure. It gave very nice warm brown tones that turned a beautiful cool chocolate tone when toned in selenium. Yes, I know part of the equation is Ektalure, and Ilford warm tone paper is not as warm. Worth a try.

GAF 135 Warm Tone Paper Developer

Water: 750ml
Metol: 1.6g
Sodium Sulfite, dessicated: 24g
Hydroquinone: 6.6g
Sodium Carbonate, monohydrated: 24g
Potassium Bromide: 2.8g*
water to make: 1.0 liter total volume.

Dilute 1:1 with water, develop 2-3 minutes at 68 degrees F. Dilute more for less contrast.

*For warmer tone, Potassium Bromide may be increased up to 5.6 g/l. Do not exceed 5.6 g/liter.

I usually used it at 5g/l of KBR.

I think this formula came from the old Photo-Lab Index.