I shoulder carry almost every day.
Carry a good quality properly functioning firearm in a proper shoulder holster & it's as safe as any other mode of carry. I would not carry in a shoulder holster if I believed that it was in any way unsafe.
Yep, Andrews Leather makes a great shoulder holster as does Lou Alessi. You are correct the Alessi is very "form fit" & tight. It needs a few shots of "Pure Silicone" spray inside the holster body to cut the friction a bit & make it just perfect.
If you carry a full weight firearm (like a Colt Govt. Model) in a shoulder rig it will (of course) pull directly down on the top of your shoulder.
It will feel uncomfortable for a couple of weeks & then your body gets very used to it. I would say that in three weeks you'll not notice it at all.
A properly constructed shoulder holster is the most comfortable, practical form of carry for the real world.
I carried every day ALL DAY for years (& usually still do) in a shoulder holster. I would never go back to carrying full time AT or ON the waist or IN the waist.
With a good shoulder holster I carry in summer just under just a darker oversize T-Shirt & its quite cool & comfy. Drawing from UNDER a T-Shirt takes practice...BUT, we are smart human beings and we get very good at what we practice often.
With practice your draw is lightning fast. I have absolutely no problems clearing my holster & having the weapon presented in one second or usually less. Summer or Winter...~ Especially with the Alessi "pull through" snap set up.
Lately...I carry in Alessi Shoulder holsters but I make my own custom harness & strap system made up entirely from orthopedic deerskin ~ VERY COMFORTABLE for 10 to 12 hour daily carry!
Try the Alessi...I know Lou Alessi & he is a damn good man. Try his holster out for a few days & if you don't like it ~ call him up & he'll take care of you.
Go out to eat...go to the movies...get in the car ~ get out of the car ~ get back in the car...sit...stand up...run...do handstands...climb a ladder ~ reach for a can on the TOP SHELF while food shopping ~ It is just the best way (for me) to carry. I usually carry in my shoulder rig from the time I get up until bed-i-boo time. I never worry about my firearm or readjust it or tug it or shift it. It's simply great. You can wear it & forget it yet always know it's right there.
There is nothing WORSE than a bad shoulder holster & nothing better than a good one. Go with quality leather. Just my humble opinion.
One reason that a shoulder rig gets a general bad rap is that you often are not permitted to draw from one at a public range. So actual "draw & fire" drills are tough to accomplish unless you own your own property. Like I do.
But, you can "dry fire" draw & shoot at home. You will get very fast.
I carry with my firearm canted slightly muzzle upward & about 2.5 to 3" under my left armpit. I carry either a Combat Commander ~ GLOCK 36 or a SIG P220 with no problems at all. The gun does not "flop around" if... you set your holster up properly. After you get it exactly how you like it then cut off all that extra long strap leather.
If you are extremely overweight then you'll probably have trouble drawing from a shoulder holster. Don't buy one.
I go everywhere with a shoulder holster & I never flash or print.
Also: People say that when you carry in a horizontal shoulder holster you "cover" everybody around you...well I hate ta break the news to you but when you carry at the waist & you walk around on your second floor...You are covering the tops of the heads of all your family members walking around on the first floor below you. You just can't see them down there but your floor sure won't stop an AD or ND ~ Think about that for a few minutes.
Buy a top quality firearm. Put it in your high quality holster (let me check to see if the naughty word bleeper is working) and don't **** with it & you'll be just fine.