Set a loss limit before you start spinning
Deciding how long to play Country Farming starts with one fact: nobody can say in advance when the Free Spins will come. The bonus frequency is not known before a spin lands, and the result of one session is random. The RTP does not change that. It describes returns over a very large number of spins, not the outcome of your next visit.
Checking the RTP version before you bet means opening the game rules, because only the rules show which version runs here. The figures table lists both versions, but the rules decide which one plays. Read that line before you stake real money.
Planning around the top prize starts with the ceiling. The maximum win of Country Farming is 10,000 times the bet, and it is reached very rarely. At the highest bet of A$240 that ceiling is A$2,400,000. Treat it as a ceiling, not a target.