[HNTFSH]

It's all about how it feels and fits. Start there and run with it. I've never bothered with extended chokes, what's that doing for you?

 

[HNTFSH]

While I don’t notice a difference in patterning between my flush and extended tubes, I like the fact that the extended chokes provide some protection for the barrel. I find the extended ones are also much easier to change out. For whatever reason, I like the look of them as well

Keep in mind, if you haven't pulled the trigger yet (see what I did there?), barrel length and gun length are two different things.

Why "fit" rules. My Citori O/U w/30" smoke poles is 2 inches shorter in overall length than my 20ga 870 w/28" barrel. Know you're not factoring in an O/U I guess but as Rick said, it needs to be an extension of you.