I know we have had possums on our property although I have not seen any recently.
What is best trapping method?
The answer depends on a lot of things. If its just an urban backyard, go for a timms trap or a trapinator. If you are connected to a bush reserve and will have reintroduction then you will need more than one. If you are worried about kiwi you will have to raise them off the ground.
The best trapping method is probably leg-holds but they have their own set of issues that may not be suitable.
How big is your property? Does it have bush on it? Do you have cats/dogs?
enviroMate100 permanently pre feeding and SA3 Steve Allen Kill traps set every 14 days.