if you look at my 870 i just put together, i put the truglo gobbler stopper in mine. Its a somewhat tight pattern but very forgiving at 25 yard, i pretty much set this gun up for my GF, and she has done great practicing with it, just need a turkey to come in now.
I used the magblends, 25 yards does about a 1 1/2 foot spread much more forgiving than my 12g shooting longbeard. but this set up will also kill a bird out to 40 no problem.
this is pretty cheap as well choke, if this dont work ive heard tighwad would be another good choise.