Senior class winners were settled at the weekend, with Scott taking the four-stroke over-300cc class honours and Watts winning the four-stroke under-300cc class.
Other senior class winners were Yeoman (two stroke over-200cc class); Dannevirke's Ben Paterson (Yamaha, two-stroke under-200cc class); Waipukurau's Stephen Sergeant (Kawasaki, veterans' 35-44 years class); Feilding's Hugh Lintott (KTM, veterans' over-45 years class); Auckland's Charlotte Russ (Yamaha, women's class) and Te Awamutu's Jack Carmichael (Husqvarna, under-19 class).
Sitting second in the junior points before the start of Sunday's racing was Te Awamutu's Nixon Parkes (KTM) and, with Hannon opting not to travel to the race on Sunday, it left the way clear for Parkes to step up and take the junior race victory at this final round, thereby joining Scott and Hannon as one of only three riders to win a race outright this season.
Parkes finished Sunday's 90-minute junior race five minutes clear of runner-up Blake Lusk (New Plymouth, Yamaha), with Taupō's Josh Yeoman (Yamaha) completing the junior podium.
In the battle for overall honours in the junior grade (behind Hannon), Parkes' win on Sunday gave him the nod over Lusk, New Plymouth's Josh Houghton (Husqvarna) and Josh Yeoman.
In the battle for junior bike class titles, Hannon had already sealed up the four-stroke over-200cc title, while Parkes collected the two-stroke over-85cc title and Eketāhuna's Ollie Corbin (KTM) won the under-85cc class.
Motorcycling New Zealand cross-country commissioner Chris Smyth said Sunday's racing was a "stern test of character" with heavy rainfall overnight turning parts of the course into a quagmire.
"It was one of the wetter events we've had in the past 10 years of running this series. It makes winning, or even just finishing, an event like this all that much sweeter," he said.
"It was great to see a couple of the senior riders from past years putting something back into the sport too, with Brad Groombridge coaching Nixon Parkes and Kevin Hermansen coaching Ben Paterson to some great successes.
"This series wouldn't have been possible without the ongoing sponsorship of Yamaha New Zealand and also thanks to the support of bike parts and accessories wholesaler Northern accessories."