Williamson has hopped off last-start winner Monnay to team up with Galleons Triumph in the same race.
Galleons Triumph, who is resuming after a spell, will start from the unruly mark behind the 20m tapes. Monnay is 30m further behind on the 50m mark with King Kenny. The other Phil Williamson-trained runners are The Silver Fox, off the front, and Miss Pegasus off 30m.
''The handicaps were more the thing there,'' Matthew Williamson said.
''Monnay's going to be off 50m and that's going to be really tough.
''It's a really sharp field and Dad's horses are really good chances.''
The Sundon gelding has four wins to his credit, but did blow his chances at times during his last campaign.
''He's one of those horses that can start really good but sometimes he just misses away and in a couple of his other runs, he's pulled during the running,'' he said.
''He is actually forward going into it but it will come down to runs between about five horses who gets the trip.
''The start will be the key to his chances. He's a good sit-sprint type horse.''
Williamson rates the chances of the well-bred One Two Kenny in the 2600m maiden trot, after she backed up her sixth on debut at Winton last month with a third at Ashburton on June 1.
''Her first start was just all right but she went really good at Ashburton and she's come forward from there so hopefully, she'll be a chance.''
The daughter of One Under Kenny (11 wins) is a likely improver out of this campaign once she is given more time to grow.
''She's quite a big horse so she will get way better in time.
''With a spell, hopefully she'll be a lot better.''
The 3yr-old will start from position two on the front line which should give her a good chance to lead.
''She led at her first start and she was third or fourth away last start,'' he said.
''Her run the other day was the run of a nice maiden and, hopefully, she can keep building on that.''
Williamson has a relatively quiet day at Oamaru. Luckee's Cruisin (race 3) is still on the way up, and may need the run under her belt.
''She goes all right, but she's one that probably needs a wee bit of racing yet. She's a bit lazy and green.''