yeh that is the right process, but 1.13 to 1.18 is pretty far away. Use sports punter >> https://www.sportspunter.com.au
Look for values on the side which are below 102%.
Try find values which are simiilar, eg $1.9 and 1.95. 1.8 and 2.2. 1.6 2.4 etc. 1.5 to …etc. Sometimes you may only need to turn over your initial deposit at odds above 1.01, in that case you can just hit a $1.2 favourite and then back the other side on the suggested bookmaker.
Lets use this as an example >> https://www.sportspunter.com.au/sports-betting/aussie-rules/australia/afl/match-betting/west-coast-vs-richmond/
Lets say we claimed a $500 Bonus Bet with Crownbet, and we have $500 real money sitting in there.
Richmond are 1.92 on Crownbet
Westcoast are 2.02 on Palmerbet/Madbookie
We then head to this calc >> “2 way Dutching Calc” setting” https://profitkings.wpengine.com/calculator/#/dutching-2way/dutching-2way
It tells us to place $500 on Richmond, and $475 on Wescoast. We lose $15 unlocking the money, but in the process of turning the bonus over made anywhere from $350 – $420.
Hope this made sense