Alot plays in with what holster you choose to have I use a Fobus mini 1911 holster if you want more adjustments the best to buy would be a BlackHawk holster but it will cost you twice the price.
I think the secret to concealing a larger pistol is properly matching the holster and the clothing with the activity and dress level required.
For example, riding in a car all day in a suit, I might use a shoulder rig. In business casual dress, a t-shirt holster or belly band might work best and if I can dress casual, I will use a high rise belt rig and wear a longer coat in the cooler season and a vest in warmer months.
I think the best way to get started is to get started and figure what works best and what your comfortable with. My wife carries a small .38 revolver and I carry a larger Colt .45 Officers and recently a .45 Colt Defender.
The extra weight of my 5" 1911 doesn't make it harder to conceal, just less comfortable. Barrel length is pretty much a moot point if you wear jeans IMO, which is why I never understood why someone would prefer a 3" 1911 for concealed carry. The grip is still long, that's what prints through a shirt. They are a bit lighter, maybe that's why.
If you dress appropriately you can conceal almost anything. It usually just comes down to person preference and what you are comfortable with. If you want to wear minimal extra clothing you might have to choose a smaller gun which will carry less rounds and probably be in a smaller caliber. If you don't want to go anywhere without a 5 inch barrel and ten rounds that can be done you might just have to wear a jacket to cover it up.
You must dress around the gun. I have worn a vest to the office everyday for the last couple of years. Different colors and materials. Everyone knows it as part of my look. Several co-workers know I carry daily and sometimes try to guess what and where I am carrying. I find a shoulder rig is most comfortable and best access for sitting at the desk or in the car.Often its a full size 1911 or Browning HP. Other times a 6 1/2" N frame or 7 1/2" Super Blackhawk. With a good shoulder rig, the weight isn't a problem. Other times, a CZ97 in a high ride by UBG or the little 442 Smith in a Ross thumb-break (almost looks like a Blackberry). All depends what fits you best and the style of dress.
Of course, nothing helps like a quality holster and a stiff gun belt.
I am 5'5" so concealment means overall gun size has to be compact to subcompact to carry comfortably. Grip length is huge in concealing. Barrel length is important for comfortable carry.
Rimfire ammo is vastly less reliable than centerfire. You are more likely to have a misfire, FTE or FTF with a P22. With a revolver, you only have the chance of misfire and all you have to do is pull the trigger again.
For the record, I would never advise carrying a .22 for SD, but if you must, get a revolver.
I have two different guns I carry. My favorite is a Beretta INOX 32 the other is a Jimenez 32. The Jimenez is thinner and fits my IWB. The beretta fits in my cargo pockets very nicely. During the summer I wear modern kilts all the time, they have cargo pockets and it is verh hard to tell if I am cc.