If your shooting is to be done at close range, a modified ( or even IC) tubeis an excellent idea... At close ranges, a super tight choke is a definite handicap, especially when the adrenaline factor kicks in...Of course, as others have said, you should pattern your gun... Also, you could save yourself some $$ and perhaps open your pattern somewhat by using less expensive lead loads rather than the Hevishot...I see no advantage with the Hevishot at such close ranges..At 30 yards or less, lead # 6 shot will work just fine...

Some years back I used a Browning Citori as a turkey gun...I put the ICtube in the under barrel and the fulltube in the over barrel...With heavy loads of # 6 or 7 1/2 lead shot, the IC tube was absolutely devastating out to 25 yards or so, and the pattern was big enough so that it was hard to miss with..