If you expect more long term support you better be paying me for my time.
1) If you want to send a PR we charge $1000 to review them. This is no guarantee that we will merge. We will quote any further costs needed after a review.
2) Feature requests should be accompanied by a $250 quotation fee. Then we will scope and quote what is required to do your feature. If your feature would compromise the project, or is impractical a started we retain the right to refuse to quote or suggest more work is required. The $250 fee is non returnable.
Something like that?