I have a Stockholm in the bridge of my SG Junior and it can go pretty heavy. I wouldn't have any qualms about a Stockholm set in an SG with two pickups.
They can screech a bit though when playing through my high-gain Peavey amp, especially if in a cramped environment where you have to stand fairly close. I've been adding shielding paint and a harness made of shielded military-grade wire to hopefully reduce that. It worked on my Explorer (which used to do the same before I shielded it, when it had a Warpig set), so hopefully it will work on this one. Also remember to cut a bit of the thin foam in the pickup box and put it on the bottom of the cavity. That can also help as long as you don't use too much and interfere with the height adjustment.
I don't know if the Stockholm is exactly what you are looking for - it might be a bit 'modern' to reproduce '60s or '70s sounds - but this clip of a Epiphone 50th Anniversary SG with Supermassives (which are basically lower-output versions of the Stockholm) is encouraging.
You might want to ask BKP if they can do a Supermassive wind for the neck pickup for better cleans.
http://www.youtube.com/watch?v=p6pG2Rg4duIThe other guitarist in my band has the stock version of this guitar and personally I think these Supermassives kill what he has in there, but he's too cheap to upgrade it :lol:
Also, see this:
http://www.youtube.com/watch?v=f3BX0wgwypQI'd also add this in case you decide to go humbucker:
Any of the BKP P-90s will work. I'm not sure why, but they do. SGs are much more picky about humbuckers.
Avoid any humbucker with strong mids and low mids, like an alnico Nailbomb or a Painkiller. You don't have to worry about a pickup being 'scooped'. The SG has a natural mid hump so when you add a scooped pickup to that the guitar fills out the scoop and everything ends up nice an balanced. I have a Cold Sweat in my SG Standard and it works beautifully. I had an A-Bomb in there (before I moved it to my Explorer) and it was awful, no versatility, very nasal and awful for Sabbath (good for AC/DC though, but it could only do that, the Exploited, Poison Idea, etc). The Miracle Man is another scooped pickup that is perfect for SGs. The C-Pig also works well in SGs. Most of the great clips I've seen of a C-Pig have been in an SG. A ceramic Nailbomb will also, from what I have heard, work okay. Otherwise go for a low output one like a Riff Raff.
Avoid the Holy Diver and Crawler (they have a reputation for muddiness in SGs). I would also probably avoid most of the Vintage Hot range. Maybe the VHII would work, but I'm not sure. I'd steer clear of the others.
The Mississippi Queen neck and Riff Raff bridge combo works well.
I'm assuming that your SG Standard has humbuckers as all Standards besides the 2012 P-90 Standard do, and you have a JB in there at present.