With a closer usage set to "aggressive" I'm afraid your ballpark spindoctors will not get the opportunity to play "bad to the bone" very often. I don't believe that Eck will enter a game UNLESS it's a save situation. In some cases I've seen a situation in the 9th become a save situation (it was not when the 9th inning started) and the music never played for my closer because HAL never put him in. I usually have my closer setting on "normal" and that seems to be the right setting to get my closer into the most games.
Eck is a great closer..no doubt...but when you pay that much scratch for one guy you want to get your money's worth. I would set him up as setup man vs. LH and closer vs. both. You might be so bold as to also set him as setup man vs. RH as well. If you see that RHs are killing him, then pull the plug on that experiment & set him back the other way (setup vs. LH/closer vs. both) and try to minimize the RH batters.
Just my .02
Good luck.