Cheap new turkey gun choke recommends
 

I just finished up cleaning and repairing 16 guns given to a buddy from his now deceased F.I.L. estate. Upon returning the guns, 7 were ill taken care of black powder pistols and rifles, my buddy asked which gun I wanted to take along for helping him get estimates and cleaning the guns up.
I told him it wasnt necessary, just gave me something to do. He insisted and would not take no for an answer so I selected a 11-87 Special Purpose 2 barrel 12ga. I was going to make it a "Stash" away gun but then decided to make an extra turkey gun with the short barrel, rifled sights and choke tubed. What tube has everyone found to work with this particular weapon. I already have a stack of Remington Hevi-Shot in various loads for turkeys and now have accumulated a pile of Win. Long Beard XR in 5's and 6's. Im open for suggestions and recommendations only as long as they are with hands on experiences. Thanks. I am going to use the existing rifled sights, no optics planned as of now.

Go to oldgobbler.com, you will probably find your answer. They have sections just for gun and chock combos.

Thanks. I will look these places up and see up from there.

Choke tubes
 

I've found the Hs undertaker to be a great patterning choke

You used the word "cheap" in your question. So....as a cheap place to start, I'd look at what Remington has. You may be surprised how well some factory chokes perform on your gun, compared to some after market chokes.

FYI...Chokes designed for heavier-than-lead shot are wider than chokes designed for lead shot.