Holster.......you can end up with a box of useless ones, I guess that is why you are asking questions about where to begin.
It is all about application and like stated above if you can design your own, MECO can make it.
I would however stay away from the Uncle Mikes/ De Santis Nemisis type, while they would appear to work well, they seem to only work well when not needed as a holster but rather a place to store the pistol while not in your pocket.
Now to try and help you decide.
I have both the Split and a Rear pocket made by Meco. Both well crafted, both function well as a pocket holster as designed.
Depending on your pocket size could make your decision for you. In 5.11 type pants, the rear pocket holster would probably only work in the front pocket, there are no traditional back pocket in these designed pants.
In Jeans, the Meco back pocket holster would easily fit the bill for either front or rear pocket, only if you wear larger pants and the pockets can accommodate it.
I'd suggest the split and wear it in the front pocket.
That's me, I'm not in love with back pocket carry.
Good luck on what you decide, but I think you are doing the best thing in asking others first.