I do occasionally in a horizontal rig. It is a two handed operation to re-holster. On the other hand it keeps it out of the way under a coat and off the waist. Especially nice for driving.
gramps
I use the Kangaroo Carry shoulder holster for my SR9c and plan to use the same one for the SP101 when I get it. The 2 guns are close to the same length, within 2oz. loaded and I'm pretty sure it will work fine. This is an inside the shirt soft type holster that is very comfortable, and better for driving then any IWB types for quick access.
I'm sure you're not as cheap as I am,but I took the stretchable leg bands of two Gerber LMF knives(they clip together) and put them around my chest.My iwb with clip fits anywhere from center chest to under my arm.This is what I use when I ride my motorcycle because my jacket is short and will ride above my belt sometimes.I usually carry my sp101 center of chest and there's no sign I'm carrying at all.You may be able to find some straps like these for cheap and they're on and off in a second.The clips are like what's on the Maxpedition bags/backpacks.Just a thought..
I'm not able to post pictures.I think the gerber lmf had two straps so that's how I had both.You might can find one long elastic strap to do the same job.The elastic stays put and just use a clip-on inside the pants holster.Might could do the same thing with a leather belt or one of the wilderness belts but don't know how comfortable it would be.Wrap a belt around your chest and clip the holster on with the holster inside the belt and the clip over to the outside and you have the idea of what I'm talking about.Hides very well.
I usually carry my 2 3/4 inch Speed Six in an Uncle Mike's vertical shoulder holster. I find it to be quite comfortable. http://www.unclemikes.com/products/sidekick_vertical_shoulder_holsters.html
$28.95 from Optics Planet. http://www.opticsplanet.net/2-3-inch-barrel-small-and-medium-double.html
I plan to order another one for my Mark II Bull Barrel. After 25 years and considerable use, one of the snaps has finally worn out. The rest of the holster is in great shape. Hard to beat the price.
The uncle Mike's I have is 26+ years old. The plastic thing on the back broke while in Alaska. Probably due to the cold. Otherwise in fine condition. I used it initially for my gp-100, which I sold. Now I use the uncle'mike's for my Redhawk.
gramps
A lot of people poo-poo nylon holsters like Uncle Mike's, but I've always had good luck with them. They don't hold moisture, don't generally rub the finish as bad as leather, and over time tend to mold themselves just fine to the gun. What's not to like?
Yep...good holsters..period. Wear forever. I even found a place where I can get a "Pull to Dot" snap....saved $28.95 on a new holster for my Mark II...good for another 30 years (even if I am not).