I have purchased custom made choke tubes for my Nova from a guy in Michigan that makes them as a hobby and will make them any size restriction you may want for no additional cost and if your gun is not on his current list he will make it for your gun for free.
I've pattern this choke tube (Mod.& Imp. Mod) Using #2/3.5 Win. Steel
at 35 and 45 yrds. At 30-40 yrds the best patterns.
Oh...and half the price of patternmaster
They go for $ 29.99 plus $5 shipping for Benelli
But If he does not make one for your gun,You may be eligible for the free choke program that he offers.
Contact Todd Wilson / firstname.lastname@example.org
or go to his website at www.wilsonprecision.com
Tell him Bob from Indiana referred you..
Hope that helps
Upside Down & Feet Twitchin...
The HeviShot way