Shell lenght ???

[Zazu45]

Hi again.

All of you guys info has been VERY MUCH apreciated, Thank's a lot.

My toughts about gun model, gauge and shot size have been confirmed.
Now for the one item I never had to chose from until now, :shell lenght. What to buy ?
3in. Mag or 3 1/2in.
I heard and read all kind of very controversial stuff about one versus the other.
So here goes: what works, what's best ???

Denis