Back pocket? No.
Back pocket would have increased potential to release magazine when seated.
Back pocket would slow access if seated in vehicle.
Back pocket hardly offers the option to "discretely" put hand on it without revealing you are carrying.
Front pocket? Yes.
Offers option to "discretely" put hand on it without revealing I'm carrying which I can't do with the Glock that is AIWB - This is my primary reason for 2nd gun.
In weak hand front pocket, it offers quick access with weak hand if needed.
Imagine trying to draw a gun from strong hand pocket with weak hand.
On a related note, location nor anticipated threat were factors in my carrying a 2nd gun; the 2nd gun affords options.
Whenever 2nd guns are discussed and people respond with comments about area, threat assessment, or
"war zone" they are not thinking about options; I realize reading my rationale of having options is unlikely change unmalleable minds.
On a related note part two, went shooting yesterday and shot the two pistols I usually carry as 2nd guns one hand weak hand, since they are carried in weak hand pocket.
One hand weak hand I shot my Sig 365 quicker than my Kahr PM9 and prefer the trigger on the sig.
At least if my dominant hand is ever in a cast or injured I already have practiced one hand with my weak hand and already have a pistol carried for weak hand access.