This is an interesting question actually. Let me offer this, you can look at this two way.
First, what is the market willing to pay? Through that lens, I would argue that Tanev return do in fact set the market for D at this trade deadline, but I think that people may under estimate the value of that D prospect in the deal. From what I read, Conroy really wanted him, so he may have valued him quite a bit and thus may have left some "currency" on the table. Wasn't it reported that some team offered their 1st? So... what is the value of the Tanev return here?? Without knowing what where the other offer, this is still a bit open for debate, and could possibly be close to the Chiarot return.
Now, what I find more interesting though here is this: KH asked for a 1st for Chiarot. He got his 1st. He asked for a 1st for Monahan. he got it. He asked for a first for Lehkonen, he got a prospect that was recently drafted there and a 2nd. So going back to your question: Is Chiarot still a benchmark? I would say: once KH set a price, he get it or no deal. that is the benchmark. So in some way, yes, chiarot set the MO of KH and certainly give reason to believe that to move Savard, it will require the price "reported" in the media.
my conclusion is that all things considered, Chiarot is, while informative, irrelevant. We can't fully compare the Tanev deal to it and we dont know what KH is really asking for Savard. The only thing i pretty sure is that if KH as set a price.... there is no way around it.