I agree, best to use delaware or almost any breed roo over the ranger type hens than the other way around.
I have black and freedom rangers. Tried for months to get fertile eggs from a black and a freedom roo over NN hens. Zero from the freedom, despite the fact he was among the smallest roos... a few from the black.
I put the freedom roo with freedom hens, he was finally able to breed successfully, but still, he messed up the hen's feathers really bad.. and one day, two hens had the skin totally ripped from their backs down to their breasts and one had deep open scratches down her side.
I have to keep him separate from all hens and only put hen in with him either until he breeds her or take her out after 10 minutes.
The older he gets, the more he fills out and it is becoming obvious he is having more difficulty breeding even the really big freedom hens. Struggles to get on, stay on and get the vents to meet.
btw- the blacks are taller and not as heavy as the freedoms, still they are bigger than most LF hens. The freedom is not able to breed them either. Right now he can only really breed the two massive hens that are almost as big as him.