Fee selection for transaction
10 satoshis/byte would have gotten you a confirmation in five days for big parts of the past three months:

 [via https://core.jochen-hoenicke.de/queue/#3m, filter by 10-20 sats/byte]

Yet, I'm afraid that you cannot rely on getting a confirmation within five days at 10 satoshis/byte.

In the past three months, there were e.g. two weeks in August, where only a few blocks had transactions with &lt;10 sats/byte. It's very likely that you would have gone without confirmations for sixteen days. Earlier this year from early May to mid of June, you would not have gotten any confirmation at all for six weeks.

Also, please think about your users' experience. When they end up with a large number of very small unspents, it will be uneconomic for them to spend them: a big portion would get eaten up by fees, at higher fees they would be unable to make any payments at all.

Unfortunately, since the cost of transactions is in relation to the blockchain space transactions require to get confirmed, the relative cost is significantly higher for micropayments than for larger sums. I would highly recommend looking either at off-chain solutions or other blockchains.