Wow, I never even noticed the first bunch of replies to my thread, let alone the fact that the thread itself got necro'd! A couple days after posting the original and having seen no responses I just stopped looking at it. This is cool that it actually generated response, and useful response at that.
To answer the question, yes I also went ahead and made this change in my campaign. My target numbers were every three points, so they'd be 9, 12, 15, 18, 21, 24 and so on. I did keep in the skill modifier and 1/2 level bonuses, and took those into account when generating my DC "chart" for the characters. It seemed to work well and the PCs liked it... and it also generated little character moments where a PC would make some insane roll, and I might grant them a continuing boon because of it. (Like my paladin player rolled an insane Athletics check to Jump... like one 6 exploded 5 times or something... so I went ahead and granted the character the Long Jumper feat for free just because).
After a while though... it became a little bit of a hassle in that the d6s just exploded a little too often for my tastes. Trying to assign useful DCs became just a little too fidgity, plus I got those insane explosions a bit too often where it lessened the impact of them. Exploding d10s in 7th Sea seemed rare and exciting when they happened... exploding d6s occurred often and became commonplace. I just lost the taste for using the system for D&D skill checks. I went back to using the standard d20 + mod rolls, but just changed things up where I never assigned DCs for things meant to be found by Passive skills (thereby telling me even before the party arrives whether or not they were going to be successful in perceiving/insighting said thing), and instead had said thing roll its own check against the PC's Passive Perception / Insight as the DC.