I have a kicks gt .665 for my 3" vinci 28" barrel.I've tested quite a few lead loads through it and while the patterns were very even it did not put up good numbers in the 10" at 40 yrds.I agree with Reynolds that the sweet spot seems to be .650-.660 in these
barrels.It just depends on the ranges that you do the most shooting at and what kind of pattern you are looking for.If you are looking to maximize your pellet count at 40 yrds with lead loads I would start with the .655 in the kicks choke.If most of your shots are in the 25-35 yrd range I would opt for the .660-.665.In this choke I would suggest the ww hv 3" #5 or 6s, the fed turkey thug #5 or 6s,winchester xx 3-2-5s,ww "grey box" 3-1/78-5s or maybe try these new ww longbeard loads.If you go to the pattern board section you can see what other members are shooting for chokes and loads,got a lot of good info on there.The benelli's have a smaller bore so generally they liked to be choked tighter than a standard bore gun like the rem 870 or the overbored guns like the moss835/brwng/win.Good luck !