My try: Il faut avoir l'avis de quelqu'un d'aussi avisé qu'expérimenté que vous.
I’m stuck on how to express the idea:
someone as wise and experienced as you
OR more literally: someone as wise as they are experienced (as you)
because two different ideas are involved and compared here:
quelqu'un d'aussi avisé qu'expérimenté
AND: quelqu'un d'aussi avisé{expérimenté} que vous
I’m not sure how to get around this duality problem and express the idea naturally in French. I think that my sentence needs some improvement.
UPDATE:
The use of "et" between "avisé" and "expérimenté" would solve the problem nicely. What I want to find out here, though: What if you start your sentence saying "quelqu'un d'aussi avisé qu'expérimenté" and then need to add the second idea "quelqu'un d'aussi avisé{expérimenté} que vous" as an afterthought? Using two "que"s like this sounds clumsy, I suppose.