I bought a Nova 12ga 28 '' barrel a short while ago for trap and so far I have been very happy.
I am not a very experenced trap shooter so I am not an expert, but it brings the clays down.
I have a M1 Super 90 with the 18.5 barrel, one range I shot at, the min barrel lenght is 24 so no go, the other doesnt have that restriction but I have not had the time go try out the M1 S90.
One post that I read said that barrel lenght is not that important its more the choke, we'll see.
I am 6' 245 recoil is not a problem then again I am shooting target loads. I still ma get the recoil reducer.