After playing dudley for all this time since release, those are my opinions of some dudley matchups. Most of them played against very good players that know their stuff and to play their character at the top of european level, not particular order in their category:
Very Hard (7-3) : Chun-Li
Hard (6-4) : Boxer, Rose, Rufus, Zangief, Honda, Abel, Guile, Ibuki, Akuma
Slight disadvantage (5.5-4.5) : Ryu, Ken, Fei Long, Dhalsim, Sagat, Cody, Cammy
Even (5-5) : Adon, Dictator, Viper, Deejay, Elfuerte, Gouken, Guy, Juri, Makoto, Seth, Claw
Favorable (4-6): Hakan
Those are the characters I feel I know the matchup pretty well right now, the ones that are out there it´s because I didnt had a chance of playing against a top player that used them.
Im still doubtful at the sagat matchup, but even if its a 6-4 it feels very winnable for me even if sagat has very very nice pokes (his walkspeed is what makes his footsies not great, but he has very good pokes) and zoning tools.
Im a bit busy those days, but ill try to break down every matchup and read at least some basics for them.
Ill try to upload some videos also playing against good shoto players as I feel most dudley players have most the troubles against them.