Hi all punter, need to get opinion from all you buddy on the topic mention above. When do you normally place a eachway bet in a race and when is the best time to place a trifecta to get good return.

I have tried once during year 2000 Melbourne Cup where I place 30 dollars on trifecta and I won 1700+ for 1/2 unit from Vic TAB. I roll 1 of my favourite (which I think will get a place and normally is not a favourite horse in the race)with 5 other horses (normally favourite with 2 medium odds and 2 outsider). I think this give me a good value bet. I did the same for last years Mel 2001 but just miss out on the second horse. Two of my pick came out 4th and 5th. A little bit off. Need your advice...