There are always several possible implementations of each placement, even within the same genre. The potential effectiveness of each of those options depends on the varying game and its audience.
The only way to confirm the hypothesis of which implementation could work best for that particular product is to conduct A/B tests. Without them, it is simply impossible to guess or calculate success. As per timing, it's best to prepare A/B test infrastructure before the first monetisation test.
For example, you need to A/B test the moment when the ad appears for the first time. The earlier the first ads are shown in playtime, the more players will see them and the higher the Day 0 LTV will be. But the first display of ads provokes player's churn, so this setting should be A/B-tested to see which timing option gives the best LTV results.
At first, it is easiest to focus on the implementation of placements like those of the closest competitors. Look at their games and analyse what they use most: Interstitial, Rewarded Videos or Banner Ads. Also, note the basic parameters for placements:
- what is the trigger for the showing (whether it is end of level, closing of the debriefing screen, start of level, timer during game session)
- when the moment of the first display of advertising to the player takes place (can be tied to the progress of levels in the game or to a specific game event in games without a level structure)
- which delay on ad display is used (how much time passes between two advertisements in the game. The average delay is 35 sec, bet this parameter should be A/B-tested, too
Rewarded placements do not have as much detailed setup as interstitial ones. The most common rewards for watching an ad are increasing rewards for completing a level, getting new game items, or resurrection in case of failure.
In the process of iterating the project, it is necessary to test different settings for each placement in order to find the composition that will be the most effective in terms of monetisation.