I think you are going to be hard pressed to find a palce where there are 170" consistantly. Very few deer even have the genetics to get that big. Overall, I think the choice that you have made is best. However, he may just want to pass those 150"'s that he has been killing and try to shoot one (a 170") at home. That way he can go on a hunt for ELK... it's pretty easy to get them over 170" consistantly!
Good luck. TGK