I'd start with a belt holster first - there are a number of folks that are moving away from shoulder holsters for various reasons, but the Hollywood force is strong, grasshopper!
I also defy 'conventional 'Net wisdom' and prefer retention straps on 'bout all my holsters.
'Course, you remember the four rules of gun safety?
How's that shoulder holster of your choice going to square with those rules?!
I once had a shoulder holster for a 6" Python years ago, but it held the gun vertically, barrel down, but I don't see many of those for semi-autos advertised.
I have a real problem with shoulder rigs that point to the rear (you want that person in front of you in the checkout line?), and if it holds the gun barrel up, you run the risk of an AD/ND severing your subclavian artery, and there is no outside pressure point for hemmorage control of a severed subclavian - so, you shoot yourself, you bleed out!
If I were you, I'd invest a little money in
The Gun Digest Book of Concealed Carry - the info you're going to get on the 'Net is like a box of chocolates, and folks just don't seem to have the ability (or desire) to weigh the pros / cons of their choices.
For reasonably priced (discounted at Optics Planet and eBay vendors), quality holsters that you won't have to wait three months for, I've had good luck with various DeSantis rigs.
Something like their
Thumb Break Scabbard gives you options (strong side or crossdraw) and a retention strap.
And as others have no doubt already told you...go ahead and get yourself a holster box!
:banghead: