after using the same strings for over a decade, i have recently changed over to SIT strings, and i gotta say, they are awesome, so far.
for a long time SIT has been pretty much the only game in town for lower-than-low-b strings, so i've been using their .165's forever for low f#, and even experimented with the .195's a bit too, but just last week i got my first shipment of their full sets, and i have to say i'm very pleased with the tone and feel.
for the longest time, the only 7 string sets offered were not the best gauges, so when i got my strings from dean markley i would have to get individual custom gauges. about 5 years ago i told bill conklin about the gauges that i used - lighter in the a, d and g than the standard gauges at the time, and heavier on the low f#, low b and high c/b and f/e, and he contacted SIT and got them to make him sets with those gauges that he now sells from his site.
ironically, instead of ordering individual strings with my prefered gauges, now i get conklin sets from SIT that have the gauges that i have always used but had to originally get special order from dean markley. so if you get a custom conklin, you are probably getting one with the SIT strings on it, with my gauges

. i tried to get bill to put my initials on the box or something

but he won't return my calls heh.
they are exposed core, and normally i haven't been a fan of exposed core (i liked tapers, down to the last winding) but the tone of these guys is really sweet, so i think i'm a happy convert. we'll see how they hold up over time.
the gauges i use now for my 7/8 strings are .165"-.135"-.110"-.080"-.055"-.-35"-.030"-.025", stainless, and very present, bright and aggressive.