Re: SG Special needs a little push!
Yo man, I have been there.....and then some.
With the DSL you probably don't need a distortion pickup. But that is up to your taste.
The bridge of many SG's is bright. On many models the bridge pickup is actually closer to the bridge than on, let's say, a Les Paul (check it out - you'll see what I mean). That is just asking for that hard, shrill biting qualiuty that is hard to dial out. The neck pickup usually sounds full, bassy, etc. So the "phenomenon" is usually the bridge only. A warm, semi powerful pickup that has some treble rolled off is what I like to compensate.
I have tried the stock Gibsons, Duncan C5, Custom, JB, DiMarzio Air Zone and Breed bridge.
I did not like the Custom or C5 because they were too bright. The C5 doesn't have a lot of mids, so it didn't "fill up" the sound and all I'd hear in the band was the upper end whcih to my ears sounded thin.
The Custom was better, but the ceramic magnet is a bit harsh in a slot that is already plagued by harshness.
Many players site the all mahogany body as a reason that "warm" pickups will be too much. Not in an SG as far as I'm concerned. Remember, the SG's body is much thinner than that of Les Paul. It is not the same equation.
Having said all that, I currently have a JB/'59n in #1 SG, and a DiMarzio Breed/PGn in #2 SG (the one in my avatar).
That has been my set up for over a year and it has worked very well.
Right now I am in a bit of a transitional phase, and I want a bit less treble from the JB, and a bit MORE treble from the '59n.
Just ordered a Jazz neck that is going in tomorrow, and am curious about the CC and Rio BBQ to replace the JB.
But, to address your issue, these pickups (to my ears) have worked very well in an SG's bridge slot to warm it up and take away the shrillness:
JB, Air Zone, Breed bridge.
All are very similar in that they are voiced in the mids (and get they articulation from the upper midrange as opposed to the treble).
The JB is the brightest of the three (but still not as bright as the Custom of C5). Great, classic sounding pickup.
Air Zone is the cleanest and most open. A little less "push" than the JB with more bass and less treble.
Breed is the warmest and punchiest. Like the Air Zone but with a bit more "push" in the mids. Also has more bass & less treble than the JB.
Keep in mind, they are all VERY similar. These differences are not all that dramatic.
These are what have been the answer for me. Still haven't tried the CC or BBQ which are both supposedly a logical option as well.
Also, you can replace the bridge pickup's volume and tone pots with 250k pots and that will roll off some of that treble.
Good luck!