Lammas and Shamal also finished third in last year's Great Northern Steeplechase over the Ellerslie hill, a path Duncan is likely to take again safely through tomorrow's assignment.
Meanwhile, Waverley trainer Harvey Wilson is aiming for a memorable Grand National Carnival week.
The former three-time Olympian lined up his entire jumping team of two last weekend and came away with a win from It's A Wonder in the Yesberg Insurances Koral Steeplechase (4250m) and a runner-up finish from Bad Boy Brown in the Racecourse Hotel & Motor Lodge Sydenham Hurdles (3100m).
Bad Boy Brown was then beaten a lip by Alfie Dee in the Grand National Hurdles on Wednesday, so have the chance to turn the tables on Duncan tomorrow with It's A Wonder.
Wilson was rapt to see steeplechaser It's A Wonder do everything right to secure his victory and placed plenty of credit for the win on the shoulders of rider Shaun Phelan.
"Shaun rode him a treat," Wilson said.
Phelan had opted to ride it's A Wonder instead of sticking with Chocolate Fish in the Grand National Steeplechase on Saturday.
Iain Hyndman's Riccarton Tips
1: Sir Ritchie, Class Above, Revolution
2: Middagurd, Turncoat, Vasiliki
3: Chuck A Luck, Cee Sharp, Pure Class
4: Galway Garry, Ahyum, Karm 'N' Easy
5: Wafer, Ophelia Lee, Red Forest
6: Shamal, It's A Wonder, Des De Jeu
7: Red Sierra, Heni, King Cougar
8: Duke Of Plumpton, Tryfan, Humble Pie
9: Dez, Rosewood, Nomen Ludi
10: Mamba, Gloss, Nathan Detroit
Best Bet: Mamba (R10)