CM,
If you are wanting to shoot saboted slugs through a choke tube, the only ones I would recommend are the extended rifled tubes. Browning made a very good one (Win-Choke) they used in the earlier A-Bolt slug guns. A Browning Rep told me the tube barrel was more accurate than the fully rifled barrel in their testing, but everyone wanted a fully rifled barrel, so they had to give them what they wanted. Now the A-Bolt slug gun is not made any longer, but they are good ones.
Remington also made a extended rifled tube (Rem-Choke), that does well also. My son has a short flush mount rifled tube in his 870 that we shoot rifled Foster slugs out of, it does such a great job that we have never shot it with the included IC choke. We have never tried saboted slugs out of the short rifled tube, since it shoots Brenneke's and Winchesters so well.