usually, ortho/para regioselectivity is something most difficult to predict: steric factors are not the only game in town
additionally, we at times observe a high dependency of the very fines of reaction conditions. For example, a reaction showing a certain distribution o/p might have a totally different distribution when changing temperature or solvent
however, there is the rule of thumb that with not too much sterical hindrance (and no other factors like neighboring group effects involved) , you usually will get more o than p product.
regards
Ingo