Does anyone have experience with KT 170's?

Seven years ago when I first purchased my VAC signature IQ monos, I chose KT 150's as the tube of choice.  I had listened to the KY 88s and 120s at the dealership and they seemed to lack punch and seemed a bit anemic compared to the KT 150's.  I have been pleased with the sound until recently. Over time, I have steadily upgraded the rest of my system with a VAC Master with phono, Nordost Valhalla 2 interconnects and speaker cables into Magico S7s.  Since the final pieces of the system were added, I've noticed a disproportionate increase in bass that overpowers certain recordings.  The light bulb went on when I read an old post of @Mulveling describing what I hear with the same amp.  I discussed this with Mike at Suncoast audio and he suggested either KT 88s or the KT 170s, which apparently has the "best bass control".  I've contacted VAC and have been informed that the amp should be compatible with the KY 170s, but I am going to talk to Kevin before adding them.  I love the sound of the KT 150s other than the "overpowered and overdeveloped" sound that Mulveling noted in a prior post.  Any advice would be appreciated.  If I could decrease the low bass by 30%, my sonic journey will be nearly complete.