Will take some getting used to. Feels like my fingertips are numb or something, I just can't "feel" the strings properly.
 
But sonically: just what the doctor ordered. :P

Guitar or Bass?

Bass. 
 
Incidentally, I've just tried getting back to bigger strings on the guitar - the SG would have been perfect for that. But just like I apprehended, the joints in my fretting hand index finger started getting painful after 48 hours or so.
 
So it's back to .09 for me. I can't risk making it worst.

Rain,
 
I switched to La Bella Flatwounds on the bass a while back.  I also went to a lighter guage because of the overall tension of the strings.  I had originally put Rotosound Flats, 45-105 on my Rick, but the tension was so high, that it was actually putting a lot of stress on the neck.  I started to read up on it and Rick's have a recommended tension max that they say not to exceed.  I didn't particularily like the feel of the Rotosounds either, so I went with the La Bella's, I believe 40-100 instead, based on a lot of recommendations from Rick users.  I love the feel of these strings, silky smooth, and the tension feels just right for me.
 
Thomas Infields were also HIGHLY recommended on a Rickenbacker for sound and feel.  The tension on those strings is supposed to be about as low as you can get on bass strings and people either seem to love the feel, or hate it.  Most people that chimed on TI Flatwounds, seem to REALLY like their tone.
 
I have noticed that I have lost a little bit of that distinctive Rickenbacker growl that they are known for; I get more of the McCartney sound with the flatwounds. 

I'll definitely go for a lighter gauge next time - these are way too big - .050 to .105. But since it's a short scale, it's not as bad.
 
My wife bought those when she bought the bass, as a few bass playing friends had recommended flatwounds to her. Local GC only had 2 brands/types - not much of a choice, so she just picked one, randomly.

On guitar, I have pretty much fallen back to 9's; but Hybrids, so that the 4,5 and 6 strings are a little heavier.  I was up to 11's at one point, but it caused so many issues with my tendonitus in my hands that I just play what I am comfortable with these days.  Shoot, I read somewhere that Billy Gibbons plays something like 8's...if he can get that kind of tone on that light of strings...    I have also read that Jimmy Page played 8's. 
 
 

Local GC only had 2 brands/types - not much of a choice, so she just picked one, randomly.

 
I checked every GC and mom and pop guitar store in the Dallas area and no one carries squat for Flatwounds.  All heavy guages.  My understanding is that flatwounds have naturally more tension because of the way they are made.  I ended up ordering online from Bass Strings Online.  Talk Bass is a great forum site for information on anything Bass related.

MakeShift
On guitar, I have pretty much fallen back to 9's; but Hybrids, so that the 4,5 and 6 strings are a little heavier.  I was up to 11's at one point, but it caused so many issues with my tendonitus in my hands that I just play what I am comfortable with these days.  Shoot, I read somewhere that Billy Gibbons plays something like 8's...if he can get that kind of tone on that light of strings...    I have also read that Jimmy Page played 8's. 
 
 

I didn't know for Gibbons, but, yeah Page definitely uses small gauges. Same for Tony Iommi, because of his missing fingertips. According to his website:
 
Here are Tony’s string gauges on the live guitars:

For the D# tuning,
.008p, .008p, .011p, .018w, .024w, .032w.

For the C# tuning,
.009p, .010p, .012p, .020w, .032w, .042w. 
 
 
Actually, .09 -.42 I usually use don't offer as much resistance as I'd like them to on the SG, hence why I was looking to try bigger ones. But the .10 won't work, not tuned to 440 anyway. To bad because 1/2 a step lower and they're perfect, but I need to commit to 440 on the projects I'm working on. And between the lack of grip and my fingers giving up on me, the choice is simple.
 
The hybrids are the ones I'd previously tried - I loved them, but after a year or so, they started hurting my fingers. But I loved the sound I got out of them.

I use the GHS custom lites 9-46 on my SG. I like the sound of the fat low E. :)

I used GHS for a while and I loved them a lot - but I happened to break a bunch a E strings in a row. There could have been a bunch of different reasons I guess, but the first thing I tried was to try Ernie Ball Slinkies instead. Never had the issue again. Could have been just an unlikely run of bad luck with strings, but I stayed w/ Slinkies since.
 
Someday I'll give those GHS another try.