Looks ok by me @ 20 for sure, That pattern should kill birds @ 40 too, from what I can see on there, no big holes in it. To try either #6 or maybe a xtra full Undertaker shud close it up @ 40 though, I'd try the #6 first, maybe you know someone else you can bum a couple off to try? Had really good luck with wwsupreme buffered #6 and an undertaker in three different guns, so, I have faith in that choke,too. It's not a wallet buster either.
Less than hevishot or nitro, and definitely more effective than #7 anything, unless it's under 30 yds.