26" is a good choice. I have a 26" shooting Hevi 3"-2-#7 with the hevi-13 tube and it is very impressive. I believe that the longer barrel may be easier to find that "magic" combination, however, others are getting awesome numbers with shorter barrels. It is a roll of the dice finding the right choke. I hope you find the right choke tube right off the bat and save yourself time and money.