I need to ask, why not use HIVEPay? Hive account@blainjones is super helpful and can help with any matters of integration if necessary (sorry for putting you on the spot here mate).

Plus, (directing to Hive account@achim03) you can choose what tokens can be used to pay (LEN or others), and put the processing fee of HIVEPay into the user. I mean, it's quite minimal... and we can easily start operating within multiple organizations helping each other.

Being a witness for Hive-Engine (Hive account@atexoras.witness), I can only see the huge benefit of doing this.