The free Hyperfocus confugration should fit just right for the majority of users. Hyperfocus is meant to be free, and allow everyone to follow the ergonomic breaks timings recommended by the research studies and the medical experts.
However, based on our past experiences using the app, we've found the short and frequent eye breaks to be the ones that provide the most comfort, with no context loss.
We still strongly recommend that you do move every single hour, maybe even every half hour. This is a critical aspect of cardiovascular health... Blood that is stagnant tends to clot.
Another tip would be using the overlay theme that you find the least comfortable, since that will make you move your sight away from the screen the fastest. The pitch black theme is worth mentioning, since it fades out your screen completely, leaving only the Hyperfocus contextual information present.
The unskippable breaks provide the best experience if you develop an immediately-click-skip reflex and we consider it to be the best feature of HF+, since it provides a high value for those of us that have a tendency to find any possible way to skip the breaks and maintain the mental flow, at the detriment of our physical health.
We fully understand that getting out of the flow is no fun, but neither is the risk of developing conditions that might decrease your vision or affect your health, many of which are hard to impossible to reverse.
In time, the seconds you'll be looking away from the screen will hardly hurt your flow zone, in fact, you might actually use them to get a fresh perspective on your current task, and take a break from objective thinking, while gaining some increased creativity.
For the custom timings, the themeable overlays and the unskippable breaks feature, a HF+ subscription is required.