Top jockey Felix Coetzee has come up with an old-fashioned idea to put himself out of his misery as far as choosing the right Tony Cruz runner for tomorrow's Group Two Chairman's Trophy (1,600 metres) at Sha Tin and is relying on his luck. 'I've tossed a coin - it's as simple as that,' Coetzee said yesterday after he selected Perfect Partner over Bullish Luck. 'And even now I've made the choice and been booked for Perfect Partner, I'm not convinced I'm on the right horse.' While Coetzee is enjoying what will probably wind up as one of his most successful seasons, the Chairman's Trophy is part of an ongoing nightmare as he tries to ride the 'correct' stable runner in high grade races. In January's Group One Stewards' Cup, Coetzee chose Perfect Partner over Bullish Luck due to his preference for the 1,600m only to be tipped off Perfect Partner at the start and have his mount scratched while Bullish Luck and Christophe Soumillon surged to an authoritative win in the first leg of the Triple Crown. When he switched horses to Bullish Luck for the suitable 2,000m of the Hong Kong Gold Cup in the second leg, the field had gone only 200m when Coetzee already knew he had jumped the wrong way. Perfect Partner - once again ridden by Soumillon - was able to dictate the lead in a very slow tempo then sprint home hard to make it impossible for rivals, including Bullish Luck, to run him down. 'They have both trained beautifully, they are both spot on and you can make a case for each of them,' he said. 'With Perfect Partner drawing gate two, I'm a bit happier because that gives us plenty of options depending on the tempo. John Size has four runners, including High Intelligent and Gem Of India who can both race handy, so he probably holds the key to the pace but it doesn't look like a lot of speed and I think Perfect Partner is a bit more adaptable in that regard.' Bullish Luck must be ridden quietly in the early stages, quite possibly a disadvantage in the race, but Coetzee is still well aware of the Stewards' Cup result. 'Yes, he has to be ridden back but there was a slow pace in the Stewards' Cup and he still swooped down the outside and outsprinted them at this distance,' he said. 'And that was in a field of 12 runners. This time there is one less horse for him to get past. It was a very difficult choice indeed.' In other news, the stipendiary stewards will today reconvene their inquiry into an unusual urine sample provided by jockey Eddie Lai Wai-ming at last Sunday's Sha Tin meeting. Stewards were advised earlier this week by Dr Terrence Wan See-ming, Head of Racing Laboratory, that the urine sample provided by Lai 'was somewhat unusual in appearance in that it lacked any distinguishing colour' and detailed his concerns regarding the sample. Lai was interviewed on Tuesday at the opening of an inquiry into the matter and provided a second urine sample for analysis, whereupon the matter was adjourned.