I use the Longbeard XR #5 out of my 12ga Ithaca and my son's 20ga Weatherby. I prefer the non-magnum load in #5 because I prefer the extra velocity - I know from my bird last year that it's a lethal combination out to 70yds.
I've tried almost everything and this round gives me the most consistent pattern and lethal down-range penetration. I tried the hevi-shot and hevi-shot choke out of son's 20ga and it didn't perform well - the penetration was there but couldn't get a consistent pattern.
Haven't tried the TSS out of the 20ga, I may give that a go, but I think it's too late now - I don't think I can get TSS delivered and/or find it locally in time for the season (starts April 18).