Super siblings Poco Dorado, Blue Moon Rising, Veloce Nero and Two Times Twice, who between them have won 96 races, clash in Saturday night's inaugural Zoom Top Flying4 at Wentworth Park with the draw favouring Poco Dorado.

All are trained by John Finn and his wife Minnie has plumped for Poco Dorado as the likely winner of the 720m duel.

"She has drawn the extreme outside and that is where she wants to be,'' Finn said.

"Poco Dorado's third to Bago Bye Bye in the big final at Albion Park last week was a really good effort because she got crowded early, something she does not like, yet she still ran home strongly.

"That indicates Poco is going as well as ever and she should win on Saturday, so long as Two Times Twice, who wants to get off the track and has box one, is not immediately inside her at the first turn.''

Len Harris has nominated Lenray Bonus, who has box one in Saturday night's ninth race, a 520m fifth grade, as the greyhound most likely to replace the ageing Cosmic Bonus as his family's major bread-winner.

Cosmic Bonus, who has won 49 of 105 races and earned nearly $354,000, is nearing the end of his career and Harris believes wife Evelyn's Lenray Bonus has the potential to pick up where the veteran leaves off.

Lenray Bonus' race on Saturday night will be a pipe opener for his appearance in the Ladbrokes Back Yourself Challenge final at Wentworth Park on July 13.

"He has earned enough points to be assured of a start in the Challenge and it's terrific to see him in box one on Saturday night,'' Len Harris said.

"Evelyn entered him for the Straight Of Origin heats at Capalaba on June 16 because they were short of dogs and he finished second before being unplaced in Precious Sal's final.

"But Lenray Bonus is better suited to a circle track like Wenty that he is on a straight course such as Capalaba.''

Lenray Bonus boasts an impressive strike rate around the circle, having won 10 of 21 contests on courses like Wentworth Park.

On Saturday Evelyn and Len Harris will make the long trip from Whiteman Creek, near Grafton, with Lenray Bonus, Bad Neighbour (race seven) and Fran's Bonus (race 10).

Len Harris said their other two starters are in top form, with Fran's Bonus being sent out a hot favourite before defeating Bad Neighbour at Lismore on Tuesday night.

"Fran's Bonus has had five wins and two thirds from her past seven starts and is a lot better now than when she was unplaced at her only Wentworth Park race in April,'' Len Harris said.

"She came in season and has improved out of sight since resuming while Bad Neighbour was a bit unlucky not to beat Fran's Bonus at Lismore on Tuesday.

"Bad Neighbour has been runner-up twice at Wentworth Park but like her kennelmate Fran's Bonus, who has drawn box five, she is awkwardly positioned in four.''

Saturday night's fifth race, a 520m fifth grade, and race eight, a Free-For-All over the same trip, loom as "dress rehearsals'' for Saturday week's heats of the group 1 events, the Peter Mosman Opal for bitches and Vic Peters Classic for dogs.

Classic hope King Kalyn (box five) takes on Opal candidates Sorry Scott (four) and Really Unreal (three) in race five while in the top grade Good Odds Harade (box eight) meets in form kennelmates Scorched (three) ands King Cratos (seven) in what should be a good guide to the Vic Peters heats.

King Cratos is a risky beginner but has won three of his four races from boxes seven and eight and should only need to step away cleanly to go close to winning.

King Kalyn took his record to five wins and two seconds from eight starts when he won on debut at Wentworth Park last Saturday and although Sorry Scott and Really Unreal have clocked faster times at headquarters, the Wenty newcomer could have more scope for improvement.

Best Bet: Lenray Bonus (race 9)

Best Value: King Kalyn (race 5)

Quaddie race 5 - 5, 4, 3

Race 6 - 7, 5, 3

Race 7 - 6, 4, 5

Race 8 - 7, 8

$20 for 37.03%