I would go with Oro because he won't engage in fight except if he really wants something or he has around 70% of winning. I would say if he fought sasori on 1 vs1 it would be 50/50 as they know how each fights. And sasori true form i bet isn't known to Oro. Sasori weaknesses can only be exploited by puppet user. So Oro could only overpower Sasori and thats why kubuto had to have 1st strick to uneven the score. Kubuto adds to Oro's victory about 5% as his medical jutsus would be inaffective against a puppet nor he could get close to sasori to attack as he would run out of chakra quickly healling posion. which leaves Oro with long range attacks and puppets of his own.