Shotgun smithing question?

[Mr. 16 gauge]

I'm looking at used O/U and SxS shotguns. I would like this gun primarily for upland hunting, so I would like open chokes (I.C. & Modified) on the gun, and I prefer 26" barrels. I hunt grouse & woodcock, but would also use the gun for pheasant, quail, rabbit, and chukar.
However, there are a lot more guns out there with tighter chokes (M &F) and 28" or longer barrels. Since there are more guns to pick from, prices are a little cheaper. My questions are:

1.) How difficult and how much (roughly) would it cost to open tighter chokes on a double barrel gun and

2.) how difficult and how much (again, roughly) would it cost to lop off a couple of inches of barrel (and have it done correctly!

My second part of this question is that I reload, and have made "spreader" loads in the past, both with the "X" inserts and the golf tee type inserts. My pattern testing indicates that they do open up chokes somewhat.
Would it be worthwhile to forgo the above mentioned smithing and just reload 'specialty' ammo for that particular gun?
Thanks in advance for your thoughts/opinions.

[skeet]

Have opened up many chokes either myself or by a smith. It is effective and is worthwhile if the gun will just be used for shorter range shots. Bird guns in the wooded country should be choked a tight cylinder and light modified. Used to be called skeet out and skeet in. My Winchester 21 20 ga is choked like that fom the factory. The Ithaca 28 ga gun is choked about the same.

But on the other hand. After I found out about thin wall chokes...I never looked back. Opening chokes on a shotgun is NOT inexpensive. Not all that much but for twice the cost or thereabouts I would send the guns to Briley and have their chokes installed. I have 8 shotguns with Briley chokes and one with Carlson's aftermarket chokes as well as a Browning BT-99 with chokes installed by Baker(who is now deceased). I would never have chokes opened again. Screw In Chokes are the way to go...and the Briley's are exceptional.. They are almost without exception better than any factory style chokes. If you have a very cheap O/U or SxS, well it may not pay. But any other grade it is usually worth it. Then you can be ready for any range shooting that may be encountered. Just opening chokes leaves a bit to be desired and they do not always shoot to the same place after having the chokes opened. Just my dos centavos

[Joe Boleo]

I asked my gunsmith to open up a full choke barrel to modified. For about the same money or a little more, I got choke tubes installed in improved cylinder and modified. Take care...
Joe